feat: add local authentication

Tiku.Infrastructure/Auth/SmsCodeHashing.cs

@@ -0,0 +1,20 @@
+using System.Security.Cryptography;
+using System.Text;
+using Tiku.Domain.Tenancy;
+
+namespace Tiku.Infrastructure.Auth;
+
+public static class SmsCodeHashing
+{
+    public static string Hash(Guid tenantId, string phone, SmsPurpose purpose, string code)
+    {
+        var normalized = $"{tenantId:N}:{NormalizePhone(phone)}:{purpose}:{code.Trim()}";
+        var hash = SHA256.HashData(Encoding.UTF8.GetBytes(normalized));
+        return Convert.ToHexString(hash).ToLowerInvariant();
+    }
+
+    public static string NormalizePhone(string phone)
+    {
+        return phone.Trim();
+    }
+}