feat: establish dotnet engineering foundation

Tiku.Api/Options/OptionsValidation.cs

@@ -1,7 +1,42 @@
+using Microsoft.Extensions.Configuration;
+using Tiku.Application.Security;
+
 namespace Tiku.Api.Options;
 
 public static class OptionsValidation
 {
+    public const string DevelopmentSigningKey = "development-only-tiku-signing-key-change-before-production";
+
+    public static string ResolveDatabaseConnectionString(
+        IConfiguration configuration,
+        bool isDevelopment)
+    {
+        var connectionString =
+            configuration.GetConnectionString("Database") ??
+            configuration["DATABASE_URL"];
+        if (!string.IsNullOrWhiteSpace(connectionString))
+        {
+            return connectionString;
+        }
+
+        if (isDevelopment)
+        {
+            return $"Host=localhost;Database=tiku;Username={Environment.UserName}";
+        }
+
+        throw new InvalidOperationException(
+            "Database connection is required outside Development. Configure ConnectionStrings:Database or DATABASE_URL.");
+    }
+
+    public static bool BeValidJwtOptions(JwtOptions options, bool isProduction)
+    {
+        return !isProduction ||
+               !string.Equals(
+                   options.SigningKey,
+                   DevelopmentSigningKey,
+                   StringComparison.Ordinal);
+    }
+
     public static bool BeValidCorsOptions(CorsOptions options)
     {
         if (options.AllowCredentials && options.AllowedOrigins.Length == 0)

Tiku.Api/Program.cs

@@ -17,6 +17,7 @@ using Tiku.Api.Security;
 using Tiku.Application;
 using Tiku.Application.Security;
 using Tiku.Infrastructure;
+using Tiku.Infrastructure.Commerce;
 using Tiku.Infrastructure.Persistence;
 using Tiku.Infrastructure.Storage;
 
@@ -133,10 +134,9 @@ try
         });
     }
 
-    var connectionString =
+    var connectionString = OptionsValidation.ResolveDatabaseConnectionString(
-        builder.Configuration.GetConnectionString("Database") ??
+        builder.Configuration,
-        builder.Configuration["DATABASE_URL"] ??
+        builder.Environment.IsDevelopment());
-        "Host=localhost;Database=tiku;Username=postgres";
 
     builder.Services.AddInfrastructure(connectionString);
     builder.Services.Configure<ObjectStorageOptions>(
@@ -172,10 +172,28 @@ try
             ? useInternalEndpoint
             : options.UseInternalEndpoint;
     });
+    builder.Services.AddOptions<TenantSecretEncryptionOptions>()
+        .Bind(builder.Configuration.GetSection(TenantSecretEncryptionOptions.SectionName))
+        .PostConfigure(options =>
+        {
+            options.KeyId = builder.Configuration["TIKU_TENANT_SECRET_KEY_ID"] ?? options.KeyId;
+            options.MasterKey = builder.Configuration["TIKU_TENANT_SECRET_MASTER_KEY"] ?? options.MasterKey;
+        })
+        .Validate(
+            TenantSecretEncryptionOptions.BeValid,
+            "Tenant secret encryption requires a key ID and a base64-encoded 32-byte master key.")
+        .Validate(
+            options => !builder.Environment.IsProduction() ||
+                       !TenantSecretEncryptionOptions.IsDevelopmentDefault(options),
+            "Production tenant secret encryption cannot use the development master key.")
+        .ValidateOnStart();
 
     builder.Services.AddOptions<JwtOptions>()
         .Bind(builder.Configuration.GetSection("Security:Jwt"))
         .ValidateDataAnnotations()
+        .Validate(
+            options => OptionsValidation.BeValidJwtOptions(options, builder.Environment.IsProduction()),
+            "Production JWT signing key must be explicitly configured and cannot use the development key.")
         .ValidateOnStart();
     var jwtOptions = builder.Configuration
         .GetSection("Security:Jwt")

Tiku.Api/appsettings.Development.json

@@ -24,6 +24,15 @@
     "WindowSeconds": 60,
     "QueueLimit": 0
   },
+  "Security": {
+    "Jwt": {
+      "SigningKey": "development-only-tiku-signing-key-change-before-production"
+    },
+    "TenantSecrets": {
+      "KeyId": "development-v1",
+      "MasterKey": "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA="
+    }
+  },
   "Storage": {
     "AliyunOss": {
       "Region": "cn-hangzhou",

Tiku.Api/appsettings.json

@@ -84,10 +84,14 @@
     "Jwt": {
       "Issuer": "tiku-backend",
       "Audience": "tiku-api",
-      "SigningKey": "development-only-tiku-signing-key-change-before-production",
+      "SigningKey": "",
       "AccessTokenMinutes": 30,
       "RefreshTokenDays": 30,
       "ValidateSessions": true
+    },
+    "TenantSecrets": {
+      "KeyId": "",
+      "MasterKey": ""
     }
   },
   "AllowedHosts": "*"

Tiku.Application/Security/JwtOptions.cs

@@ -10,7 +10,7 @@ public sealed class JwtOptions
 
     [System.ComponentModel.DataAnnotations.Required]
     [System.ComponentModel.DataAnnotations.MinLength(32)]
-    public string SigningKey { get; set; } = "development-only-tiku-signing-key-change-before-production";
+    public string SigningKey { get; set; } = string.Empty;
 
     [System.ComponentModel.DataAnnotations.Range(1, 1440)]
     public int AccessTokenMinutes { get; set; } = 30;

Tiku.DbMigrator/DesignTimeTikuDbContextFactory.cs

@@ -10,7 +10,7 @@ public sealed class DesignTimeTikuDbContextFactory : IDesignTimeDbContextFactory
     {
         var connectionString =
             Environment.GetEnvironmentVariable("DATABASE_URL") ??
-            "Host=localhost;Database=tiku;Username=postgres";
+            $"Host=localhost;Database=tiku;Username={Environment.UserName}";
 
         var options = new DbContextOptionsBuilder<TikuDbContext>()
             .UseNpgsql(connectionString, npgsql =>

Tiku.Domain/Tenancy/TenantOperationsEntities.cs

@@ -18,7 +18,10 @@ public sealed class TenantSecret : AuditableTenantEntity
     public string SecretKey { get; set; } = string.Empty;
     public string SecretRef { get; set; } = string.Empty;
     public TenantSecretStatus Status { get; set; } = TenantSecretStatus.Active;
-    public JsonElement SecretPayload { get; set; } = JsonDefaults.Object();
+    public string EncryptionKeyId { get; set; } = string.Empty;
+    public byte[] EncryptedPayload { get; set; } = [];
+    public byte[] EncryptionNonce { get; set; } = [];
+    public byte[] EncryptionTag { get; set; } = [];
     public DateTimeOffset? RotatedAt { get; set; }
     public DateTimeOffset? ExpiresAt { get; set; }
 }

Tiku.Infrastructure/Commerce/CommerceAdminService.cs

@@ -10,7 +10,9 @@ using Tiku.Infrastructure.Persistence;
 
 namespace Tiku.Infrastructure.Commerce;
 
-public sealed class CommerceAdminService(TikuDbContext dbContext) : ICommerceAdminService
+internal sealed class CommerceAdminService(
+    TikuDbContext dbContext,
+    ITenantSecretProtector tenantSecretProtector) : ICommerceAdminService
 {
     public async Task<IReadOnlyCollection<TenantPaymentAccountItem>> GetPaymentAccountsAsync(
         CommerceAdminActor actor,
@@ -88,11 +90,19 @@ public sealed class CommerceAdminService(TikuDbContext dbContext) : ICommerceAdm
             secret.RotatedAt = DateTimeOffset.UtcNow;
         }
 
+        var protectedPayload = tenantSecretProtector.Protect(
+            actor.TenantId,
+            secretRef,
+            JsonObjectOrDefault(command.SecretPayload));
+
         secret.Purpose = command.Purpose.Trim();
         secret.Provider = provider;
         secret.SecretKey = command.SecretKey.Trim();
         secret.Status = command.Status;
-        secret.SecretPayload = JsonObjectOrDefault(command.SecretPayload);
+        secret.EncryptionKeyId = protectedPayload.KeyId;
+        secret.EncryptedPayload = protectedPayload.Ciphertext;
+        secret.EncryptionNonce = protectedPayload.Nonce;
+        secret.EncryptionTag = protectedPayload.Tag;
         secret.ExpiresAt = command.ExpiresAt;
 
         await dbContext.SaveChangesAsync(cancellationToken);

Tiku.Infrastructure/Commerce/TenantSecretEncryption.cs

@@ -0,0 +1,116 @@
+using System.Security.Cryptography;
+using System.Text;
+using System.Text.Json;
+
+namespace Tiku.Infrastructure.Commerce;
+
+public sealed class TenantSecretEncryptionOptions
+{
+    public const string SectionName = "Security:TenantSecrets";
+    public const string DevelopmentMasterKey = "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=";
+
+    public string KeyId { get; set; } = string.Empty;
+
+    public string MasterKey { get; set; } = string.Empty;
+
+    public static bool BeValid(TenantSecretEncryptionOptions options)
+    {
+        if (string.IsNullOrWhiteSpace(options.KeyId) || string.IsNullOrWhiteSpace(options.MasterKey))
+        {
+            return false;
+        }
+
+        try
+        {
+            return Convert.FromBase64String(options.MasterKey).Length == 32;
+        }
+        catch (FormatException)
+        {
+            return false;
+        }
+    }
+
+    public static bool IsDevelopmentDefault(TenantSecretEncryptionOptions options) =>
+        string.Equals(options.MasterKey, DevelopmentMasterKey, StringComparison.Ordinal);
+}
+
+internal interface ITenantSecretProtector
+{
+    ProtectedTenantSecret Protect(Guid tenantId, string secretRef, JsonElement payload);
+
+    JsonElement Unprotect(
+        Guid tenantId,
+        string secretRef,
+        string keyId,
+        byte[] ciphertext,
+        byte[] nonce,
+        byte[] tag);
+}
+
+internal sealed record ProtectedTenantSecret(
+    string KeyId,
+    byte[] Ciphertext,
+    byte[] Nonce,
+    byte[] Tag);
+
+internal sealed class TenantSecretProtector(
+    Microsoft.Extensions.Options.IOptions<TenantSecretEncryptionOptions> options) : ITenantSecretProtector
+{
+    private readonly TenantSecretEncryptionOptions options = options.Value;
+
+    public ProtectedTenantSecret Protect(Guid tenantId, string secretRef, JsonElement payload)
+    {
+        var key = Convert.FromBase64String(options.MasterKey);
+        var plaintext = JsonSerializer.SerializeToUtf8Bytes(payload);
+        var nonce = RandomNumberGenerator.GetBytes(12);
+        var ciphertext = new byte[plaintext.Length];
+        var tag = new byte[16];
+        var associatedData = GetAssociatedData(tenantId, secretRef, options.KeyId);
+
+        try
+        {
+            using var aes = new AesGcm(key, tag.Length);
+            aes.Encrypt(nonce, plaintext, ciphertext, tag, associatedData);
+            return new ProtectedTenantSecret(options.KeyId, ciphertext, nonce, tag);
+        }
+        finally
+        {
+            CryptographicOperations.ZeroMemory(key);
+            CryptographicOperations.ZeroMemory(plaintext);
+        }
+    }
+
+    public JsonElement Unprotect(
+        Guid tenantId,
+        string secretRef,
+        string keyId,
+        byte[] ciphertext,
+        byte[] nonce,
+        byte[] tag)
+    {
+        if (!string.Equals(keyId, options.KeyId, StringComparison.Ordinal))
+        {
+            throw new InvalidOperationException(
+                $"Tenant secret uses unknown encryption key '{keyId}'.");
+        }
+
+        var key = Convert.FromBase64String(options.MasterKey);
+        var plaintext = new byte[ciphertext.Length];
+        var associatedData = GetAssociatedData(tenantId, secretRef, keyId);
+        try
+        {
+            using var aes = new AesGcm(key, tag.Length);
+            aes.Decrypt(nonce, ciphertext, tag, plaintext, associatedData);
+            using var document = JsonDocument.Parse(plaintext);
+            return document.RootElement.Clone();
+        }
+        finally
+        {
+            CryptographicOperations.ZeroMemory(key);
+            CryptographicOperations.ZeroMemory(plaintext);
+        }
+    }
+
+    private static byte[] GetAssociatedData(Guid tenantId, string secretRef, string keyId) =>
+        Encoding.UTF8.GetBytes($"{tenantId:N}\n{secretRef}\n{keyId}");
+}

Tiku.Infrastructure/Commerce/TenantSecretService.cs

@@ -6,7 +6,9 @@ using Tiku.Infrastructure.Persistence;
 
 namespace Tiku.Infrastructure.Commerce;
 
-internal sealed class TenantSecretService(TikuDbContext dbContext) : ITenantSecretService
+internal sealed class TenantSecretService(
+    TikuDbContext dbContext,
+    ITenantSecretProtector tenantSecretProtector) : ITenantSecretService
 {
     public async Task<JsonElement> GetActiveSecretPayloadAsync(
         Guid tenantId,
@@ -28,16 +30,28 @@ internal sealed class TenantSecretService(TikuDbContext dbContext) : ITenantSecr
                 item.SecretRef == secretRef &&
                 item.Status == TenantSecretStatus.Active &&
                 (item.ExpiresAt == null || item.ExpiresAt > now))
-            .Select(item => item.SecretPayload)
             .SingleOrDefaultAsync(cancellationToken);
 
-        if (secret.ValueKind is JsonValueKind.Undefined or JsonValueKind.Null)
+        if (secret is null)
         {
             throw new PaymentProviderException(
                 "Payment provider secret is not configured.",
                 "payment_secret_not_configured");
         }
 
-        return secret;
+        if (secret.EncryptedPayload.Length > 0)
+        {
+            return tenantSecretProtector.Unprotect(
+                tenantId,
+                secretRef,
+                secret.EncryptionKeyId,
+                secret.EncryptedPayload,
+                secret.EncryptionNonce,
+                secret.EncryptionTag);
+        }
+
+        throw new PaymentProviderException(
+            "Payment provider secret is not configured.",
+            "payment_secret_not_configured");
     }
 }

Tiku.Infrastructure/Content/ContentNavigationQueryService.cs

@@ -1,6 +1,7 @@
 using Microsoft.EntityFrameworkCore;
 using Tiku.Application.Catalog;
 using Tiku.Application.Content;
+using Tiku.Domain.Common;
 using Tiku.Domain.Content;
 using Tiku.Domain.QuestionBanks;
 using Tiku.Infrastructure.Persistence;
@@ -279,6 +280,9 @@ public sealed class ContentNavigationQueryService(TikuDbContext dbContext) : ICo
             throw new ContentNavigationNotFoundException("Question collection was not found.");
         }
 
+        var emptyOptions = JsonDefaults.Array();
+        var emptyCorrectOptionIndices = JsonDefaults.Array();
+        var emptySubQuestions = JsonDefaults.Array();
         var query =
             from item in dbContext.QuestionCollectionItems.AsNoTracking()
             join question in dbContext.Questions.AsNoTracking()
@@ -313,12 +317,12 @@ public sealed class ContentNavigationQueryService(TikuDbContext dbContext) : ICo
                 item.SortOrder,
                 version == null ? null : version.Id,
                 version == null ? null : version.Content,
-                version == null ? default : version.Options,
+                version == null ? emptyOptions : version.Options,
                 version == null ? null : version.CorrectOptionIndex,
-                version == null ? default : version.CorrectOptionIndices,
+                version == null ? emptyCorrectOptionIndices : version.CorrectOptionIndices,
                 version == null ? null : version.AnswerText,
                 version == null ? null : version.Explanation,
-                version == null ? default : version.SubQuestions,
+                version == null ? emptySubQuestions : version.SubQuestions,
                 version == null ? null : version.CodeLang,
                 version == null ? null : version.CodeTemplate);
 

Tiku.Infrastructure/Content/DirectContentService.cs

@@ -34,6 +34,7 @@ public sealed class DirectContentService(TikuDbContext dbContext) : IDirectConte
         CancellationToken cancellationToken = default)
     {
         await AssertQuestionReferencesAsync(actor.TenantId, command, cancellationToken);
+        await using var transaction = await dbContext.Database.BeginTransactionAsync(cancellationToken);
 
         var question = new Question
         {
@@ -42,6 +43,7 @@ public sealed class DirectContentService(TikuDbContext dbContext) : IDirectConte
         };
         ApplyQuestion(question, command);
         dbContext.Questions.Add(question);
+        await dbContext.SaveChangesAsync(cancellationToken);
 
         var version = BuildQuestionVersion(actor, question.Id, 1, command);
         dbContext.QuestionVersions.Add(version);
@@ -49,6 +51,7 @@ public sealed class DirectContentService(TikuDbContext dbContext) : IDirectConte
         await SyncPrimaryCollectionItemAsync(actor, question, cancellationToken);
 
         await dbContext.SaveChangesAsync(cancellationToken);
+        await transaction.CommitAsync(cancellationToken);
         return new ContentManagementResult<QuestionManagementItem>(ToQuestionItem(question, version));
     }
 

Tiku.Infrastructure/DependencyInjection.cs

@@ -74,6 +74,7 @@ public static class DependencyInjection
         services.AddScoped<IReferralService, ReferralService>();
         services.AddScoped<ICrmService, CrmService>();
         services.AddScoped<ICommissionService, CommissionService>();
+        services.AddSingleton<ITenantSecretProtector, TenantSecretProtector>();
         services.AddScoped<ITenantSecretService, TenantSecretService>();
         services.AddScoped<IPaymentProviderConfigService, PaymentProviderConfigService>();
         services.AddScoped<IPaymentProviderGateway, PaymentProviderGateway>();

Tiku.Infrastructure/Growth/CrmService.cs

@@ -4,11 +4,14 @@ using Tiku.Application.Growth;
 using Tiku.Domain.Common;
 using Tiku.Domain.Growth;
 using Tiku.Domain.Tenancy;
+using Tiku.Infrastructure.Commerce;
 using Tiku.Infrastructure.Persistence;
 
 namespace Tiku.Infrastructure.Growth;
 
-public sealed class CrmService(TikuDbContext dbContext) : ICrmService
+internal sealed class CrmService(
+    TikuDbContext dbContext,
+    ITenantSecretProtector tenantSecretProtector) : ICrmService
 {
     private static readonly HashSet<string> SensitiveKeys = new(StringComparer.OrdinalIgnoreCase)
     {
@@ -254,8 +257,15 @@ public sealed class CrmService(TikuDbContext dbContext) : ICrmService
             item.RotatedAt = DateTimeOffset.UtcNow;
         }
 
+        var protectedPayload = tenantSecretProtector.Protect(
+            tenantId,
+            secretRef,
+            JsonSerializer.SerializeToElement(new { webhookSecret = secret }));
         item.Status = TenantSecretStatus.Active;
-        item.SecretPayload = JsonSerializer.SerializeToElement(new { webhookSecret = secret });
+        item.EncryptionKeyId = protectedPayload.KeyId;
+        item.EncryptedPayload = protectedPayload.Ciphertext;
+        item.EncryptionNonce = protectedPayload.Nonce;
+        item.EncryptionTag = protectedPayload.Tag;
     }
 
     private async Task AssertAdminAsync(CrmAdminActor actor, CancellationToken cancellationToken)

Tiku.Infrastructure/Growth/ReferralService.cs

@@ -136,6 +136,7 @@ public sealed class ReferralService(
         var eventType = NormalizeChoice(command.EventType, AllowedEventTypes, "enter", "invalid_referral_event_type");
         var source = NormalizeChoice(command.Source, AllowedSources, "unknown", "invalid_referral_source");
         var resolution = await ResolveCodeCoreAsync(actor.TenantId, code, cancellationToken);
+        await using var transaction = await dbContext.Database.BeginTransactionAsync(cancellationToken);
         var track = new ReferralTrack
         {
             TenantId = actor.TenantId,
@@ -148,7 +149,6 @@ public sealed class ReferralService(
             UserAgent = Truncate(NormalizeOptional(userAgent), 1024),
             Metadata = command.Metadata ?? JsonDefaults.Object()
         };
-        dbContext.ReferralTracks.Add(track);
 
         ReferralLead? lead = null;
         CrmWebhookQueueItem? crmQueue = null;
@@ -164,16 +164,29 @@ public sealed class ReferralService(
                 false,
                 command.Metadata,
                 cancellationToken);
-            if (lead.FirstTrackId is null)
+            var setFirstTrack = lead.FirstTrackId is null;
+            if (setFirstTrack)
+            {
+                await dbContext.SaveChangesAsync(cancellationToken);
+            }
+
+            dbContext.ReferralTracks.Add(track);
+            track.LeadId = lead.Id;
+            await dbContext.SaveChangesAsync(cancellationToken);
+            if (setFirstTrack)
             {
                 lead.FirstTrackId = track.Id;
             }
 
-            track.LeadId = lead.Id;
             crmQueue = await EnqueueCrmIfEnabledAsync(actor.TenantId, lead, "referral.track_event", cancellationToken);
         }
+        else
+        {
+            dbContext.ReferralTracks.Add(track);
+        }
 
         await dbContext.SaveChangesAsync(cancellationToken);
+        await transaction.CommitAsync(cancellationToken);
         return new ReferralTrackResult(ToTrackItem(track), lead is null ? null : ToLeadItem(lead, true), ToQueuePreview(crmQueue));
     }
 

Tiku.Infrastructure/Persistence/Configurations/TenantOperationsConfigurations.cs

@@ -32,10 +32,14 @@ internal sealed class TenantSecretConfiguration : IEntityTypeConfiguration<Tenan
         builder.Property(entity => entity.SecretKey).HasMaxLength(120);
         builder.Property(entity => entity.SecretRef).HasMaxLength(300);
         builder.Property(entity => entity.Status).HasSnakeCaseEnum();
-        builder.Property(entity => entity.SecretPayload).IsJson("{}");
+        builder.Property(entity => entity.EncryptionKeyId).HasMaxLength(100);
         builder.HasIndex(entity => new { entity.TenantId, entity.SecretRef }).IsUnique();
         builder.HasIndex(entity => new { entity.TenantId, entity.Purpose, entity.Provider, entity.SecretKey }).IsUnique();
         builder.HasIndex(entity => new { entity.TenantId, entity.Purpose, entity.Provider, entity.Status });
+        builder.ToTable(table => table.HasCheckConstraint(
+            "ck_tenant_secrets_encryption_envelope",
+            "octet_length(encrypted_payload) > 0 and octet_length(encryption_nonce) = 12 and " +
+            "octet_length(encryption_tag) = 16 and encryption_key_id <> ''"));
     }
 }
 

Tiku.Infrastructure/Persistence/Migrations/20260727062859_EncryptTenantSecretPayloads.cs

@@ -0,0 +1,84 @@
+using System.Text.Json;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Tiku.Infrastructure.Persistence.Migrations
+{
+    /// <inheritdoc />
+    public partial class EncryptTenantSecretPayloads : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "secret_payload",
+                table: "tenant_secrets");
+
+            migrationBuilder.AddColumn<byte[]>(
+                name: "encrypted_payload",
+                table: "tenant_secrets",
+                type: "bytea",
+                nullable: false,
+                defaultValue: new byte[0]);
+
+            migrationBuilder.AddColumn<string>(
+                name: "encryption_key_id",
+                table: "tenant_secrets",
+                type: "character varying(100)",
+                maxLength: 100,
+                nullable: false,
+                defaultValue: "");
+
+            migrationBuilder.AddColumn<byte[]>(
+                name: "encryption_nonce",
+                table: "tenant_secrets",
+                type: "bytea",
+                nullable: false,
+                defaultValue: new byte[0]);
+
+            migrationBuilder.AddColumn<byte[]>(
+                name: "encryption_tag",
+                table: "tenant_secrets",
+                type: "bytea",
+                nullable: false,
+                defaultValue: new byte[0]);
+
+            migrationBuilder.AddCheckConstraint(
+                name: "ck_tenant_secrets_encryption_envelope",
+                table: "tenant_secrets",
+                sql: "octet_length(encrypted_payload) > 0 and octet_length(encryption_nonce) = 12 and octet_length(encryption_tag) = 16 and encryption_key_id <> ''");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropCheckConstraint(
+                name: "ck_tenant_secrets_encryption_envelope",
+                table: "tenant_secrets");
+
+            migrationBuilder.DropColumn(
+                name: "encrypted_payload",
+                table: "tenant_secrets");
+
+            migrationBuilder.DropColumn(
+                name: "encryption_key_id",
+                table: "tenant_secrets");
+
+            migrationBuilder.DropColumn(
+                name: "encryption_nonce",
+                table: "tenant_secrets");
+
+            migrationBuilder.DropColumn(
+                name: "encryption_tag",
+                table: "tenant_secrets");
+
+            migrationBuilder.AddColumn<JsonElement>(
+                name: "secret_payload",
+                table: "tenant_secrets",
+                type: "jsonb",
+                nullable: false,
+                defaultValueSql: "'{}'::jsonb");
+        }
+    }
+}

Tiku.Infrastructure/Persistence/Migrations/TikuDbContextModelSnapshot.cs

@@ -12958,6 +12958,27 @@ namespace Tiku.Infrastructure.Persistence.Migrations
                         .HasColumnName("created_at")
                         .HasDefaultValueSql("now()");
 
+                    b.Property<byte[]>("EncryptedPayload")
+                        .IsRequired()
+                        .HasColumnType("bytea")
+                        .HasColumnName("encrypted_payload");
+
+                    b.Property<string>("EncryptionKeyId")
+                        .IsRequired()
+                        .HasMaxLength(100)
+                        .HasColumnType("character varying(100)")
+                        .HasColumnName("encryption_key_id");
+
+                    b.Property<byte[]>("EncryptionNonce")
+                        .IsRequired()
+                        .HasColumnType("bytea")
+                        .HasColumnName("encryption_nonce");
+
+                    b.Property<byte[]>("EncryptionTag")
+                        .IsRequired()
+                        .HasColumnType("bytea")
+                        .HasColumnName("encryption_tag");
+
                     b.Property<DateTimeOffset?>("ExpiresAt")
                         .HasColumnType("timestamp with time zone")
                         .HasColumnName("expires_at");
@@ -12984,12 +13005,6 @@ namespace Tiku.Infrastructure.Persistence.Migrations
                         .HasColumnType("character varying(120)")
                         .HasColumnName("secret_key");
 
-                    b.Property<JsonElement>("SecretPayload")
-                        .ValueGeneratedOnAdd()
-                        .HasColumnType("jsonb")
-                        .HasColumnName("secret_payload")
-                        .HasDefaultValueSql("'{}'::jsonb");
-
                     b.Property<string>("SecretRef")
                         .IsRequired()
                         .HasMaxLength(300)
@@ -13029,7 +13044,10 @@ namespace Tiku.Infrastructure.Persistence.Migrations
                     b.HasIndex("TenantId", "Purpose", "Provider", "Status")
                         .HasDatabaseName("ix_tenant_secrets_tenant_id_purpose_provider_status");
 
-                    b.ToTable("tenant_secrets", (string)null);
+                    b.ToTable("tenant_secrets", null, t =>
+                        {
+                            t.HasCheckConstraint("ck_tenant_secrets_encryption_envelope", "octet_length(encrypted_payload) > 0 and octet_length(encryption_nonce) = 12 and octet_length(encryption_tag) = 16 and encryption_key_id <> ''");
+                        });
                 });
 
             modelBuilder.Entity("Tiku.Domain.Tenancy.TenantSettings", b =>

Tiku.Infrastructure/QuestionBanks/QuestionBankQueryService.cs

@@ -1,6 +1,7 @@
 using Microsoft.EntityFrameworkCore;
 using Tiku.Application.Catalog;
 using Tiku.Application.QuestionBanks;
+using Tiku.Domain.Common;
 using Tiku.Domain.Content;
 using Tiku.Domain.QuestionBanks;
 using Tiku.Infrastructure.Persistence;
@@ -222,6 +223,9 @@ public sealed class QuestionBankQueryService(TikuDbContext dbContext) : IQuestio
 
     private IQueryable<QuestionCatalogItem> ProjectQuestions(IQueryable<Question> questions)
     {
+        var emptyOptions = JsonDefaults.Array();
+        var emptyCorrectOptionIndices = JsonDefaults.Array();
+        var emptySubQuestions = JsonDefaults.Array();
         return
             from question in questions
             join version in dbContext.QuestionVersions.AsNoTracking()
@@ -253,12 +257,12 @@ public sealed class QuestionBankQueryService(TikuDbContext dbContext) : IQuestio
                 version == null ? null : version.Id,
                 version == null ? null : version.VersionNo,
                 version == null ? null : version.Content,
-                version == null ? default : version.Options,
+                version == null ? emptyOptions : version.Options,
                 version == null ? null : version.CorrectOptionIndex,
-                version == null ? default : version.CorrectOptionIndices,
+                version == null ? emptyCorrectOptionIndices : version.CorrectOptionIndices,
                 version == null ? null : version.AnswerText,
                 version == null ? null : version.Explanation,
-                version == null ? default : version.SubQuestions,
+                version == null ? emptySubQuestions : version.SubQuestions,
                 version == null ? null : version.CodeLang,
                 version == null ? null : version.CodeTemplate);
     }

Tiku.Infrastructure/TenantAdmin/TenantAdminDirectService.cs

@@ -1263,7 +1263,7 @@ public sealed class TenantAdminDirectService(TikuDbContext dbContext) : ITenantA
             GrantedBy = actor.UserId,
             GrantedAt = command.GrantedAt ?? DateTimeOffset.UtcNow
         };
-        grant.LegacyId = Normalize(command.LegacyId) ?? grant.LegacyId ?? $"badge:{command.BadgeId}:user:{command.UserId}";
+        grant.LegacyId = Normalize(command.LegacyId) ?? grant.LegacyId;
         grant.Note = Normalize(command.Note) ?? grant.Note;
         grant.GrantedBy ??= actor.UserId;
         grant.GrantedAt ??= command.GrantedAt ?? DateTimeOffset.UtcNow;
@@ -1272,19 +1272,20 @@ public sealed class TenantAdminDirectService(TikuDbContext dbContext) : ITenantA
             dbContext.UserBadges.Add(grant);
         }
 
+        var dedupeKey = $"badge:{grant.Id:N}";
         var notification = await dbContext.UserNotifications.FirstOrDefaultAsync(
             item =>
                 item.TenantId == actor.TenantId &&
                 item.UserId == command.UserId &&
                 item.NotificationType == "badge_granted" &&
-                item.DedupeKey == grant.LegacyId,
+                item.DedupeKey == dedupeKey,
             cancellationToken);
         notification ??= new UserNotification
         {
             TenantId = actor.TenantId,
             UserId = command.UserId,
             NotificationType = "badge_granted",
-            DedupeKey = grant.LegacyId,
+            DedupeKey = dedupeKey,
             CreatedBy = actor.UserId
         };
         notification.Severity = NotificationSeverity.Success;

Tiku.IntegrationTests/Api/ApiTestFactory.cs

@@ -7,7 +7,9 @@ using Tiku.Application.Auth;
 using Tiku.Application.Growth;
 using Tiku.Application.Storage;
 using Tiku.Domain.Identity;
+using Tiku.Domain.QuestionBanks;
 using Tiku.Domain.Tenancy;
+using Tiku.IntegrationTests.Infrastructure;
 using Tiku.Infrastructure.Persistence;
 
 namespace Tiku.IntegrationTests.Api;
@@ -18,7 +20,7 @@ public sealed class ApiTestFactory(
     IReferralQrcodeGenerator? referralQrcodeGenerator = null,
     IPaymentProviderGateway? paymentProviderGateway = null) : WebApplicationFactory<Program>
 {
-    private readonly string databaseName = Guid.NewGuid().ToString();
+    private readonly PostgresTestDatabase database = PostgresTestDatabase.Create();
 
     protected override void ConfigureWebHost(Microsoft.AspNetCore.Hosting.IWebHostBuilder builder)
     {
@@ -34,8 +36,13 @@ public sealed class ApiTestFactory(
                 services.Remove(descriptor);
             }
 
-            services.AddDbContext<TikuDbContext>(options =>
+            services.AddSingleton(_ => NpgsqlDataSource.Create(database.ConnectionString));
-                options.UseInMemoryDatabase(databaseName));
+            services.AddDbContextPool<TikuDbContext>((serviceProvider, options) =>
+            {
+                var dataSource = serviceProvider.GetRequiredService<NpgsqlDataSource>();
+                options.UseNpgsql(dataSource, npgsql =>
+                    npgsql.MigrationsAssembly(typeof(TikuDbContext).Assembly.FullName));
+            });
 
             if (wechatOAuthClient is not null)
             {
@@ -67,6 +74,20 @@ public sealed class ApiTestFactory(
         await dbContext.SaveChangesAsync();
     }
 
+    public async Task SeedQuestionWithVersionAsync(Question question, QuestionVersion version)
+    {
+        question.CurrentVersionId = null;
+        await SeedAsync(question);
+        await SeedAsync(version);
+
+        using var scope = Services.CreateScope();
+        var dbContext = scope.ServiceProvider.GetRequiredService<TikuDbContext>();
+        var persistedQuestion = await dbContext.Questions.SingleAsync(item =>
+            item.TenantId == question.TenantId && item.Id == question.Id);
+        persistedQuestion.CurrentVersionId = version.Id;
+        await dbContext.SaveChangesAsync();
+    }
+
     public async Task<Guid> SeedActiveSessionAsync(
         Guid userId,
         Guid? tenantId = null,
@@ -102,4 +123,13 @@ public sealed class ApiTestFactory(
             .Select(session => session.Id)
             .SingleAsync();
     }
+
+    protected override void Dispose(bool disposing)
+    {
+        base.Dispose(disposing);
+        if (disposing)
+        {
+            database.Dispose();
+        }
+    }
 }

Tiku.IntegrationTests/Api/AssetEndpointTests.cs

@@ -1,7 +1,9 @@
 using System.Net;
 using System.Text.Json;
 using Tiku.Domain.Common;
+using Tiku.Domain.Catalog;
 using Tiku.Domain.Content;
+using Tiku.Domain.QuestionBanks;
 using Tiku.Domain.Tenancy;
 
 namespace Tiku.IntegrationTests.Api;
@@ -16,6 +18,7 @@ public sealed class AssetEndpointTests
         await using var factory = new ApiTestFactory();
         await factory.SeedAsync(
             Tenant(tenantId, "master"),
+            new Region { Id = regionId, TenantId = tenantId, Name = "测试地区" },
             new ContentAsset
             {
                 Id = Guid.NewGuid(),
@@ -162,6 +165,13 @@ public sealed class AssetEndpointTests
         await using var factory = new ApiTestFactory();
         await factory.SeedAsync(
             Tenant(tenantId, "master"),
+            new Question
+            {
+                Id = questionId,
+                TenantId = tenantId,
+                Type = "choice",
+                Status = QuestionStatus.Published
+            },
             new VideoExplanation
             {
                 Id = videoId,

Tiku.IntegrationTests/Api/CatalogEndpointTests.cs

@@ -299,12 +299,16 @@ public sealed class CatalogEndpointTests
         var tenantId = Guid.NewGuid();
         var regionId = Guid.NewGuid();
         var schoolId = Guid.NewGuid();
+        var otherRegionId = Guid.NewGuid();
+        var otherSchoolId = Guid.NewGuid();
         var futureExamAt = new DateTimeOffset(DateTimeOffset.UtcNow.Date.AddDays(10), TimeSpan.Zero);
         await using var factory = new ApiTestFactory();
         await factory.SeedAsync(
             Tenant(tenantId, "master"),
             new Region { Id = regionId, TenantId = tenantId, Name = "浙江" },
+            new Region { Id = otherRegionId, TenantId = tenantId, Name = "其他地区" },
             new School { Id = schoolId, TenantId = tenantId, RegionId = regionId, Name = "测试院校" },
+            new School { Id = otherSchoolId, TenantId = tenantId, RegionId = otherRegionId, Name = "其他院校" },
             new ExamDate
             {
                 Id = Guid.NewGuid(),
@@ -327,8 +331,8 @@ public sealed class CatalogEndpointTests
             {
                 Id = Guid.NewGuid(),
                 TenantId = tenantId,
-                RegionId = Guid.NewGuid(),
+                RegionId = otherRegionId,
-                SchoolId = Guid.NewGuid(),
+                SchoolId = otherSchoolId,
                 ExamName = "其他地区学校考试",
                 ExamAt = futureExamAt.AddDays(2),
                 IsActive = true
@@ -420,10 +424,12 @@ public sealed class CatalogEndpointTests
     {
         var tenantId = Guid.NewGuid();
         var regionId = Guid.NewGuid();
+        var otherRegionId = Guid.NewGuid();
         await using var factory = new ApiTestFactory();
         await factory.SeedAsync(
             Tenant(tenantId, "master"),
             new Region { Id = regionId, TenantId = tenantId, Name = "浙江" },
+            new Region { Id = otherRegionId, TenantId = tenantId, Name = "其他地区" },
             new SvipPlan
             {
                 Id = Guid.NewGuid(),
@@ -449,7 +455,7 @@ public sealed class CatalogEndpointTests
             {
                 Id = Guid.NewGuid(),
                 TenantId = tenantId,
-                RegionId = Guid.NewGuid(),
+                RegionId = otherRegionId,
                 Name = "其他地区卡",
                 PriceCents = 1000,
                 Days = 7,

Tiku.IntegrationTests/Api/ContentNavigationEndpointTests.cs

@@ -1,6 +1,7 @@
 using System.Net;
 using System.Text.Json;
 using Tiku.Domain.Common;
+using Tiku.Domain.Catalog;
 using Tiku.Domain.Content;
 using Tiku.Domain.QuestionBanks;
 using Tiku.Domain.Tenancy;
@@ -17,6 +18,7 @@ public sealed class ContentNavigationEndpointTests
         await using var factory = new ApiTestFactory();
         await factory.SeedAsync(
             Tenant(tenantId, "master"),
+            new Region { Id = regionId, TenantId = tenantId, Name = "测试地区" },
             new ContentEntry
             {
                 Id = Guid.NewGuid(),
@@ -193,23 +195,6 @@ public sealed class ContentNavigationEndpointTests
                 Status = ContentStatus.Active
             },
             new Question
-            {
-                Id = publishedQuestionId,
-                TenantId = tenantId,
-                PrimaryCollectionId = collectionId,
-                Type = "choice",
-                TypeLabel = "单选题",
-                Status = QuestionStatus.Published,
-                CurrentVersionId = versionId
-            },
-            new QuestionVersion
-            {
-                Id = versionId,
-                TenantId = tenantId,
-                QuestionId = publishedQuestionId,
-                Content = "题干"
-            },
-            new Question
             {
                 Id = archivedQuestionId,
                 TenantId = tenantId,
@@ -218,15 +203,6 @@ public sealed class ContentNavigationEndpointTests
                 Status = QuestionStatus.Archived
             },
             new QuestionCollectionItem
-            {
-                Id = Guid.NewGuid(),
-                TenantId = tenantId,
-                CollectionId = collectionId,
-                QuestionId = publishedQuestionId,
-                SortOrder = 1,
-                Score = 2
-            },
-            new QuestionCollectionItem
             {
                 Id = Guid.NewGuid(),
                 TenantId = tenantId,
@@ -234,6 +210,32 @@ public sealed class ContentNavigationEndpointTests
                 QuestionId = archivedQuestionId,
                 SortOrder = 2
             });
+        await factory.SeedQuestionWithVersionAsync(
+            new Question
+            {
+                Id = publishedQuestionId,
+                TenantId = tenantId,
+                PrimaryCollectionId = collectionId,
+                Type = "choice",
+                TypeLabel = "单选题",
+                Status = QuestionStatus.Published
+            },
+            new QuestionVersion
+            {
+                Id = versionId,
+                TenantId = tenantId,
+                QuestionId = publishedQuestionId,
+                Content = "题干"
+            });
+        await factory.SeedAsync(new QuestionCollectionItem
+        {
+            Id = Guid.NewGuid(),
+            TenantId = tenantId,
+            CollectionId = collectionId,
+            QuestionId = publishedQuestionId,
+            SortOrder = 1,
+            Score = 2
+        });
         using var client = factory.CreateClient();
 
         using var response = await client.GetAsync($"/api/catalog/question-collections/questions?tenantCode=master&collectionId={collectionId}");

Tiku.IntegrationTests/Api/ProductionConfigurationTests.cs

@@ -0,0 +1,61 @@
+using Microsoft.Extensions.Configuration;
+using Tiku.Api.Options;
+using Tiku.Application.Security;
+using Tiku.Infrastructure.Commerce;
+
+namespace Tiku.IntegrationTests.Api;
+
+public sealed class ProductionConfigurationTests
+{
+    [Fact]
+    public void Database_connection_is_required_outside_development()
+    {
+        var configuration = new ConfigurationBuilder().Build();
+
+        var exception = Assert.Throws<InvalidOperationException>(() =>
+            OptionsValidation.ResolveDatabaseConnectionString(configuration, isDevelopment: false));
+
+        Assert.Contains("Database connection is required", exception.Message, StringComparison.Ordinal);
+    }
+
+    [Fact]
+    public void Development_database_default_uses_current_system_user_without_a_password()
+    {
+        var configuration = new ConfigurationBuilder().Build();
+
+        var connectionString = OptionsValidation.ResolveDatabaseConnectionString(
+            configuration,
+            isDevelopment: true);
+
+        Assert.Contains($"Username={Environment.UserName}", connectionString, StringComparison.Ordinal);
+        Assert.DoesNotContain("Password=", connectionString, StringComparison.OrdinalIgnoreCase);
+    }
+
+    [Fact]
+    public void Production_rejects_the_committed_development_jwt_key()
+    {
+        var options = new JwtOptions
+        {
+            SigningKey = OptionsValidation.DevelopmentSigningKey
+        };
+
+        Assert.False(OptionsValidation.BeValidJwtOptions(options, isProduction: true));
+        Assert.True(OptionsValidation.BeValidJwtOptions(options, isProduction: false));
+    }
+
+    [Fact]
+    public void Tenant_secret_encryption_requires_a_32_byte_base64_key()
+    {
+        Assert.False(TenantSecretEncryptionOptions.BeValid(new TenantSecretEncryptionOptions()));
+        Assert.False(TenantSecretEncryptionOptions.BeValid(new TenantSecretEncryptionOptions
+        {
+            KeyId = "key-v1",
+            MasterKey = Convert.ToBase64String(new byte[16])
+        }));
+        Assert.True(TenantSecretEncryptionOptions.BeValid(new TenantSecretEncryptionOptions
+        {
+            KeyId = "key-v1",
+            MasterKey = Convert.ToBase64String(new byte[32])
+        }));
+    }
+}

Tiku.IntegrationTests/Api/ProfileEndpointTests.cs

@@ -62,7 +62,11 @@ public sealed class ProfileEndpointTests
         var seed = await SeedStudentAsync(factory);
         var regionId = Guid.NewGuid();
         var schoolId = Guid.NewGuid();
+        var otherRegionId = Guid.NewGuid();
         await factory.SeedAsync(
+            new Region { Id = regionId, TenantId = seed.TenantId, Name = "四川" },
+            new Region { Id = otherRegionId, TenantId = seed.TenantId, Name = "其他地区" },
+            new School { Id = schoolId, TenantId = seed.TenantId, RegionId = regionId, Name = "美术学院" },
             new StudentProfile
             {
                 TenantId = seed.TenantId,
@@ -81,7 +85,7 @@ public sealed class ProfileEndpointTests
             new ExamDate
             {
                 TenantId = seed.TenantId,
-                RegionId = Guid.NewGuid(),
+                RegionId = otherRegionId,
                 ExamName = "其他地区考试",
                 ExamAt = DateTimeOffset.UtcNow.AddDays(1)
             });

Tiku.IntegrationTests/Api/QuestionBankEndpointTests.cs

@@ -1,6 +1,7 @@
 using System.Net;
 using System.Text.Json;
 using Tiku.Domain.Common;
+using Tiku.Domain.Catalog;
 using Tiku.Domain.Content;
 using Tiku.Domain.QuestionBanks;
 using Tiku.Domain.Tenancy;
@@ -62,8 +63,20 @@ public sealed class QuestionBankEndpointTests
         await using var factory = new ApiTestFactory();
         await factory.SeedAsync(
             Tenant(tenantId, "master"),
+            new Subject { Id = subjectId, TenantId = tenantId, Name = "测试科目" },
+            new Category { Id = categoryId, TenantId = tenantId, SubjectId = subjectId, Name = "测试分类" },
             new QuestionBank { Id = bankId, TenantId = tenantId, Name = "题库" },
             new QuestionCollection { Id = collectionId, TenantId = tenantId, Name = "题集", Status = ContentStatus.Active },
+            new Question
+            {
+                Id = excludedQuestionId,
+                TenantId = tenantId,
+                QuestionBankId = bankId,
+                SubjectId = subjectId,
+                Type = "choice",
+                Status = QuestionStatus.Archived
+            });
+        await factory.SeedQuestionWithVersionAsync(
             new Question
             {
                 Id = includedQuestionId,
@@ -74,8 +87,7 @@ public sealed class QuestionBankEndpointTests
                 Type = "choice",
                 TypeLabel = "单选题",
                 Difficulty = 2,
-                Status = QuestionStatus.Published,
+                Status = QuestionStatus.Published
-                CurrentVersionId = versionId
             },
             new QuestionVersion
             {
@@ -84,23 +96,14 @@ public sealed class QuestionBankEndpointTests
                 QuestionId = includedQuestionId,
                 VersionNo = 2,
                 Content = "题干关键词"
-            },
-            new QuestionCollectionItem
-            {
-                Id = Guid.NewGuid(),
-                TenantId = tenantId,
-                CollectionId = collectionId,
-                QuestionId = includedQuestionId
-            },
-            new Question
-            {
-                Id = excludedQuestionId,
-                TenantId = tenantId,
-                QuestionBankId = bankId,
-                SubjectId = subjectId,
-                Type = "choice",
-                Status = QuestionStatus.Archived
             });
+        await factory.SeedAsync(new QuestionCollectionItem
+        {
+            Id = Guid.NewGuid(),
+            TenantId = tenantId,
+            CollectionId = collectionId,
+            QuestionId = includedQuestionId
+        });
         using var client = factory.CreateClient();
 
         using var response = await client.GetAsync(

Tiku.IntegrationTests/Api/StudyContentEndpointTests.cs

@@ -1,6 +1,7 @@
 using System.Net;
 using System.Text.Json;
 using Tiku.Domain.Common;
+using Tiku.Domain.Catalog;
 using Tiku.Domain.Content;
 using Tiku.Domain.Tenancy;
 
@@ -16,6 +17,7 @@ public sealed class StudyContentEndpointTests
         await using var factory = new ApiTestFactory();
         await factory.SeedAsync(
             Tenant(tenantId, "master"),
+            new Region { Id = regionId, TenantId = tenantId, Name = "测试地区" },
             new VocabularyUnit
             {
                 Id = Guid.NewGuid(),

Tiku.IntegrationTests/Api/TenantCommerceEndpointTests.cs

@@ -1,6 +1,7 @@
 using System.Net;
 using System.Net.Http.Json;
 using System.Text.Json;
+using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.DependencyInjection;
 using Tiku.Api.Contracts;
 using Tiku.Application.Auth;
@@ -93,6 +94,21 @@ public sealed class TenantCommerceEndpointTests
         Assert.Equal(HttpStatusCode.OK, accountResponse.StatusCode);
         Assert.Equal(HttpStatusCode.OK, accountsResponse.StatusCode);
         Assert.Contains("wechat_pay", await accountsResponse.Content.ReadAsStringAsync(), StringComparison.OrdinalIgnoreCase);
+
+        using var scope = factory.Services.CreateScope();
+        var dbContext = scope.ServiceProvider.GetRequiredService<TikuDbContext>();
+        var storedSecret = await dbContext.TenantSecrets
+            .AsNoTracking()
+            .SingleAsync(item => item.TenantId == seed.TenantId);
+        var configService = scope.ServiceProvider.GetRequiredService<IPaymentProviderConfigService>();
+        var resolvedAccount = await configService.GetActiveAccountAsync(seed.TenantId, "wechat_pay");
+
+        Assert.Equal("development-v1", storedSecret.EncryptionKeyId);
+        Assert.NotEmpty(storedSecret.EncryptedPayload);
+        Assert.Equal(12, storedSecret.EncryptionNonce.Length);
+        Assert.Equal(16, storedSecret.EncryptionTag.Length);
+        Assert.Equal("pem", resolvedAccount.SecretPayload.GetProperty("privateKey").GetString());
+        Assert.Equal("v3", resolvedAccount.SecretPayload.GetProperty("apiV3Key").GetString());
     }
 
     [Fact]

Tiku.IntegrationTests/Infrastructure/PostgresTestDatabase.cs

@@ -0,0 +1,182 @@
+using Microsoft.EntityFrameworkCore;
+using Npgsql;
+using Tiku.Infrastructure.Persistence;
+
+namespace Tiku.IntegrationTests.Infrastructure;
+
+internal sealed class PostgresTestDatabase : IDisposable
+{
+    private const string DatabasePrefix = "tiku_it_";
+    private static readonly Lazy<PostgresTestDatabaseTemplate> Template = new(
+        PostgresTestDatabaseTemplate.Create,
+        LazyThreadSafetyMode.ExecutionAndPublication);
+    private readonly string adminConnectionString;
+    private bool disposed;
+
+    private PostgresTestDatabase(string adminConnectionString, string databaseName, string connectionString)
+    {
+        this.adminConnectionString = adminConnectionString;
+        DatabaseName = databaseName;
+        ConnectionString = connectionString;
+    }
+
+    public string DatabaseName { get; }
+
+    public string ConnectionString { get; }
+
+    public static PostgresTestDatabase Create()
+    {
+        var template = Template.Value;
+        var adminConnectionString = template.AdminConnectionString;
+        var databaseName = $"{DatabasePrefix}{Guid.NewGuid():N}";
+        var adminBuilder = new NpgsqlConnectionStringBuilder(adminConnectionString);
+
+        using (var adminConnection = new NpgsqlConnection(adminBuilder.ConnectionString))
+        {
+            adminConnection.Open();
+            using var createDatabase = adminConnection.CreateCommand();
+            createDatabase.CommandText =
+                $"CREATE DATABASE {QuoteIdentifier(databaseName)} TEMPLATE {QuoteIdentifier(template.DatabaseName)}";
+            createDatabase.ExecuteNonQuery();
+        }
+
+        var databaseBuilder = new NpgsqlConnectionStringBuilder(adminBuilder.ConnectionString)
+        {
+            Database = databaseName,
+            Pooling = true,
+            MaxPoolSize = 10
+        };
+        var database = new PostgresTestDatabase(
+            adminBuilder.ConnectionString,
+            databaseName,
+            databaseBuilder.ConnectionString);
+
+        return database;
+    }
+
+    public void Dispose()
+    {
+        if (disposed)
+        {
+            return;
+        }
+
+        disposed = true;
+        var builder = new NpgsqlConnectionStringBuilder(adminConnectionString);
+        using var adminConnection = new NpgsqlConnection(builder.ConnectionString);
+        adminConnection.Open();
+
+        using (var terminateConnections = adminConnection.CreateCommand())
+        {
+            terminateConnections.CommandText =
+                "SELECT pg_terminate_backend(pid) FROM pg_stat_activity WHERE datname = $1 AND pid <> pg_backend_pid()";
+            terminateConnections.Parameters.AddWithValue(DatabaseName);
+            terminateConnections.ExecuteNonQuery();
+        }
+
+        using var dropDatabase = adminConnection.CreateCommand();
+        dropDatabase.CommandText = $"DROP DATABASE IF EXISTS {QuoteIdentifier(DatabaseName)}";
+        dropDatabase.ExecuteNonQuery();
+    }
+
+    internal static string QuoteIdentifier(string identifier)
+    {
+        if (!identifier.StartsWith(DatabasePrefix, StringComparison.Ordinal) ||
+            identifier.Any(character => !char.IsAsciiLetterOrDigit(character) && character != '_'))
+        {
+            throw new InvalidOperationException("Refusing to use an unsafe integration-test database name.");
+        }
+
+        return $"\"{identifier}\"";
+    }
+}
+
+internal sealed class PostgresTestDatabaseTemplate : IDisposable
+{
+    private const string TemplatePrefix = "tiku_it_template_";
+    private bool disposed;
+
+    private PostgresTestDatabaseTemplate(string adminConnectionString, string databaseName)
+    {
+        AdminConnectionString = adminConnectionString;
+        DatabaseName = databaseName;
+    }
+
+    public string AdminConnectionString { get; }
+
+    public string DatabaseName { get; }
+
+    public static PostgresTestDatabaseTemplate Create()
+    {
+        var adminConnectionString = Environment.GetEnvironmentVariable("TIKU_TEST_POSTGRES_ADMIN") ??
+                                    $"Host=localhost;Database=postgres;Username={Environment.UserName};Pooling=false;Timeout=5;Command Timeout=60";
+        var adminBuilder = new NpgsqlConnectionStringBuilder(adminConnectionString);
+        if (!string.Equals(adminBuilder.Database, "postgres", StringComparison.OrdinalIgnoreCase))
+        {
+            throw new InvalidOperationException(
+                "TIKU_TEST_POSTGRES_ADMIN must target the postgres maintenance database.");
+        }
+
+        var databaseName = $"{TemplatePrefix}{Environment.ProcessId}_{Guid.NewGuid():N}";
+        var template = new PostgresTestDatabaseTemplate(adminBuilder.ConnectionString, databaseName);
+
+        try
+        {
+            using (var adminConnection = new NpgsqlConnection(template.AdminConnectionString))
+            {
+                adminConnection.Open();
+                using var createDatabase = adminConnection.CreateCommand();
+                createDatabase.CommandText =
+                    $"CREATE DATABASE {PostgresTestDatabase.QuoteIdentifier(databaseName)}";
+                createDatabase.ExecuteNonQuery();
+            }
+
+            var databaseBuilder = new NpgsqlConnectionStringBuilder(template.AdminConnectionString)
+            {
+                Database = databaseName,
+                Pooling = false
+            };
+            var options = new DbContextOptionsBuilder<TikuDbContext>()
+                .UseNpgsql(databaseBuilder.ConnectionString, npgsql =>
+                    npgsql.MigrationsAssembly(typeof(TikuDbContext).Assembly.FullName))
+                .Options;
+            using (var dbContext = new TikuDbContext(options))
+            {
+                dbContext.Database.Migrate();
+            }
+
+            using (var adminConnection = new NpgsqlConnection(template.AdminConnectionString))
+            {
+                adminConnection.Open();
+                using var preventConnections = adminConnection.CreateCommand();
+                preventConnections.CommandText =
+                    $"ALTER DATABASE {PostgresTestDatabase.QuoteIdentifier(databaseName)} ALLOW_CONNECTIONS false";
+                preventConnections.ExecuteNonQuery();
+            }
+
+            AppDomain.CurrentDomain.ProcessExit += (_, _) => template.Dispose();
+            return template;
+        }
+        catch
+        {
+            template.Dispose();
+            throw;
+        }
+    }
+
+    public void Dispose()
+    {
+        if (disposed)
+        {
+            return;
+        }
+
+        disposed = true;
+        using var adminConnection = new NpgsqlConnection(AdminConnectionString);
+        adminConnection.Open();
+        using var dropDatabase = adminConnection.CreateCommand();
+        dropDatabase.CommandText =
+            $"DROP DATABASE IF EXISTS {PostgresTestDatabase.QuoteIdentifier(DatabaseName)}";
+        dropDatabase.ExecuteNonQuery();
+    }
+}

Tiku.IntegrationTests/MigrationExecutionTests.cs

@@ -0,0 +1,25 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+using Tiku.IntegrationTests.Api;
+using Tiku.Infrastructure.Persistence;
+
+namespace Tiku.IntegrationTests;
+
+public sealed class MigrationExecutionTests
+{
+    [Fact]
+    public async Task Api_test_database_uses_postgresql_and_applies_every_migration()
+    {
+        await using var factory = new ApiTestFactory();
+        using var scope = factory.Services.CreateScope();
+        var dbContext = scope.ServiceProvider.GetRequiredService<TikuDbContext>();
+
+        var appliedMigrations = await dbContext.Database.GetAppliedMigrationsAsync();
+        var expectedMigrations = dbContext.Database.GetMigrations();
+
+        Assert.Equal("Npgsql.EntityFrameworkCore.PostgreSQL", dbContext.Database.ProviderName);
+        Assert.Equal(expectedMigrations, appliedMigrations);
+        Assert.NotEmpty(appliedMigrations);
+        Assert.True(await dbContext.Database.CanConnectAsync());
+    }
+}

Tiku.IntegrationTests/PersistenceModelTests.cs

@@ -513,7 +513,6 @@ public sealed class PersistenceModelTests
 
     [Theory]
     [InlineData(typeof(TenantAuthProvider), nameof(TenantAuthProvider.ConfigPublic), "'{}'::jsonb")]
-    [InlineData(typeof(TenantSecret), nameof(TenantSecret.SecretPayload), "'{}'::jsonb")]
     [InlineData(typeof(SmsVerificationCode), nameof(SmsVerificationCode.Metadata), "'{}'::jsonb")]
     [InlineData(typeof(AuthLoginEvent), nameof(AuthLoginEvent.Metadata), "'{}'::jsonb")]
     [InlineData(typeof(AuthSession), nameof(AuthSession.Metadata), "'{}'::jsonb")]

Tiku.IntegrationTests/Tiku.IntegrationTests.csproj

@@ -23,7 +23,6 @@
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
     <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing" />
-    <PackageReference Include="Microsoft.EntityFrameworkCore.InMemory" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" />
     <PackageReference Include="xunit" />
     <PackageReference Include="xunit.runner.visualstudio">

docs/migration-roadmap.md

@@ -6,6 +6,7 @@
 
 - [`docs/adr/0001-authoritative-dotnet-backend.md`](adr/0001-authoritative-dotnet-backend.md)
 - [`docs/migration/phase-1-repository-baseline.md`](migration/phase-1-repository-baseline.md)
+- [`docs/migration/phase-2-engineering-foundation.md`](migration/phase-2-engineering-foundation.md)
 
 迁移原则：
 

docs/migration/phase-2-engineering-foundation.md

@@ -0,0 +1,87 @@
+# 第二阶段：.NET 工程底座
+
+完成日期：2026-07-27。
+
+本阶段按 greenfield 项目建设，不承担旧 Supabase / NestJS 数据兼容。数据库结构以 EF Core 实体、Fluent Configuration 和 Migration 为唯一权威来源；API 运行时不自动修改数据库。
+
+## 数据库开发与发布边界
+
+- 开发采用 code first：修改实体或 Fluent Configuration 后生成 EF Core Migration。
+- Migration 统一保存在 `Tiku.Infrastructure/Persistence/Migrations/`。
+- `Tiku.DbMigrator` 是执行 Migration 的独立入口。
+- `Tiku.Api` 和 `Tiku.Worker` 不调用 `Database.Migrate()`，避免多实例启动时争抢 DDL，也避免应用进程持有结构变更权限。
+- 发布前生成并审查 SQL；生产环境由部署流程显式执行 DbMigrator 或审核后的 SQL。
+- Development 未配置连接串时默认连接本机 `tiku` 数据库，并使用当前系统用户名，不内置密码。
+- 非 Development 环境必须显式配置 `ConnectionStrings:Database` 或 `DATABASE_URL`，缺失时启动失败。
+
+常用命令：
+
+```bash
+dotnet ef migrations add <MigrationName> \
+  --project Tiku.Infrastructure \
+  --startup-project Tiku.DbMigrator
+
+dotnet ef migrations script \
+  --project Tiku.Infrastructure \
+  --startup-project Tiku.DbMigrator
+
+dotnet run --project Tiku.DbMigrator
+```
+
+## 真实 PostgreSQL 测试基线
+
+`Tiku.IntegrationTests` 已移除 EF Core InMemory provider，全部集成测试连接真实 PostgreSQL：
+
+- 管理连接可通过 `TIKU_TEST_POSTGRES_ADMIN` 覆盖。
+- 默认管理连接为 `Host=localhost;Database=postgres;Username=<当前系统用户>`。
+- 测试进程创建一次已执行完整 Migration 的模板数据库。
+- 每个 `ApiTestFactory` 从模板克隆独立 `tiku_it_*` 数据库，测试之间不共享业务数据。
+- Factory 释放时终止连接并删除克隆库；进程退出时删除模板库。
+- 测试只允许管理 `tiku_it_*` 命名空间，不访问或清理已有 `tiku` 业务数据库。
+
+真实关系型测试暴露并修正了以下 InMemory 无法可靠验证的问题：
+
+- 测试夹具缺失的 Region、School、Subject、Category、Question 等外键实体。
+- `Question` 与 `QuestionVersion` 当前版本引用形成的插入循环，改为事务内分阶段保存。
+- `ReferralLead.FirstTrackId` 与 `ReferralTrack.LeadId` 形成的插入循环，改为事务内分阶段保存。
+- PostgreSQL JSON 映射不能将未定义的 `default(JsonElement)` 生成为 SQL literal，缺省数组改为有效的 `[]`。
+- 徽章发放不再伪造超长 legacy ID；通知使用新记录 ID 生成独立、稳定的去重键。
+
+## 配置与密钥安全
+
+- 根配置不再提交可用于生产的 JWT signing key。
+- Development 只使用明确标识的开发 JWT key；Production 拒绝该 key。
+- 租户第三方凭据使用 AES-256-GCM envelope 保存。
+- 每条密文使用 12-byte nonce、16-byte authentication tag。
+- AAD 绑定 `tenantId`、`secretRef` 和 `keyId`，密文不能跨租户或跨引用替换。
+- 主密钥必须是 Base64 编码的 32 字节值；Production 拒绝仓库内的开发测试 key。
+- 运行时配置键为 `Security:TenantSecrets:KeyId` 和 `Security:TenantSecrets:MasterKey`；环境变量可使用 `TIKU_TENANT_SECRET_KEY_ID` 与 `TIKU_TENANT_SECRET_MASTER_KEY`。
+- 新 schema 只保留 `encryption_key_id`、`encrypted_payload`、`encryption_nonce`、`encryption_tag`，不保留明文字段或明文回退读取路径。
+
+本阶段的 `EncryptTenantSecretPayloads` Migration 会直接删除旧 `secret_payload` 字段。这是 greenfield 决策，不提供旧数据转换或兼容窗口。
+
+## 验证结果
+
+2026-07-27 在本机 PostgreSQL 18.4、.NET SDK 10.0.301 上完成：
+
+```text
+dotnet build：通过，0 warning / 0 error
+dotnet test：通过，265/265
+  UnitTests：16/16
+  IntegrationTests（真实 PostgreSQL）：249/249
+dotnet format --verify-no-changes：通过
+git diff --check：通过
+EF Core migration script：通过，生成 4184 行 SQL
+测试数据库清理：通过，无 tiku_it_* 残留
+```
+
+## 第二阶段退出条件
+
+- [x] EF Core Migration 成为 code-first schema 的唯一版本历史。
+- [x] API 与 Worker 不在启动时自动执行 Migration。
+- [x] 生产数据库、JWT 和租户密钥配置缺失时 fail fast。
+- [x] 租户第三方凭据只保存 AES-GCM 密文 envelope。
+- [x] 集成测试完全切换到隔离的真实 PostgreSQL 数据库。
+- [x] 修复真实数据库暴露的外键、循环依赖、JSON 和字段长度问题。
+- [x] 全量构建、测试、格式与 Migration SQL 验证通过。
+