Add file module for uploads and storage

- File model + migration: file metadata, content lives in object storage
- IFileStorage port with local disk and S3-compatible (RustFS/MinIO) adapters
- POST /files, GET /files/:id/download, DELETE /files/:id
- MIME sniffed from content; only safe images served inline, nosniff header
- FileOwnerRegistry: owner modules register to grant visibility and keep
  their files from GC; FileGcService removes orphaned files hourly
- TransformResponseInterceptor passes StreamableFile through

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/modules/file/infrastructure/storage/file-storage.factory.ts

@@ -0,0 +1,26 @@
+import { ConfigService } from '@nestjs/config';
+import type { IFileStorage } from '../../domain/ports/file-storage.port.js';
+import { LocalFileStorage } from './local-file-storage.js';
+import { S3FileStorage } from './s3-file-storage.js';
+
+/** FILE_STORAGE=s3 — S3-совместимое хранилище, иначе локальный диск */
+export function createFileStorage(config: ConfigService): IFileStorage {
+  const driver = config.get<string>('FILE_STORAGE', 'local');
+
+  if (driver === 's3') {
+    return new S3FileStorage({
+      endpoint: config.get<string>('S3_ENDPOINT') || undefined,
+      region: config.get<string>('S3_REGION', 'us-east-1'),
+      bucket: config.getOrThrow<string>('S3_BUCKET'),
+      accessKeyId: config.getOrThrow<string>('S3_ACCESS_KEY_ID'),
+      secretAccessKey: config.getOrThrow<string>('S3_SECRET_ACCESS_KEY'),
+      forcePathStyle: config.get<string>('S3_FORCE_PATH_STYLE', 'true') !== 'false',
+    });
+  }
+
+  if (driver !== 'local') {
+    throw new Error(`Неизвестный FILE_STORAGE=${driver}, ожидается local | s3`);
+  }
+
+  return new LocalFileStorage(config.get<string>('FILE_STORAGE_LOCAL_DIR', './storage'));
+}