feat: migrate backend foundation to NestJS

scripts/nest-migration-contract-test.js

@@ -0,0 +1,28 @@
+import assert from 'node:assert/strict';
+import fs from 'node:fs';
+
+const read = file => fs.readFileSync(file, 'utf8').replace(/\r\n/g, '\n');
+const legacyBridge = read('apps/api/src/nest/legacy-bridge.ts');
+const server = read('apps/api/src/server.ts');
+const worker = read('apps/worker/src/index.ts');
+const workerModule = read('apps/worker/src/worker.module.ts');
+
+const nativeKeys = [...legacyBridge.matchAll(/'(GET|POST|PUT|PATCH|DELETE) ([^']+)'/g)]
+  .map(match => `${match[1]} ${match[2]}`);
+assert.equal(new Set(nativeKeys).size, 50, 'the first NestJS batch must own exactly 50 unique routes');
+assert.equal(nativeKeys.length, 50, 'native route declarations must not contain duplicates');
+assert.match(legacyBridge, /definitions\.filter\(\(\[method, path\]\) => !NATIVE_ROUTE_KEYS\.has/);
+assert.match(legacyBridge, /\/api\/questions\/:questionId\/videos/);
+
+assert.match(server, /NestFactory\.create<.*NestFastifyApplication>/);
+assert.match(server, /registerLegacyRoutes/);
+assert.match(server, /if \(!config\.isProduction\) registerOpenApi/);
+assert.match(server, /ApiEnvelopeInterceptor/);
+assert.match(server, /ApiExceptionFilter/);
+
+assert.match(worker, /NestFactory\.createApplicationContext\(WorkerModule/);
+assert.match(worker, /app\.get\(WorkerRunner\)/);
+assert.match(workerModule, /constructor\(private readonly jobs: WorkerJobRegistry, private readonly intervals: WorkerPollIntervals\)/);
+assert.match(workerModule, /constructor\(private readonly closers: WorkerCloserRegistry\)/);
+
+console.log('[PASS] NestJS first-batch routes, legacy bridge, docs guard and worker DI contract');