feat(auth): add row/size caps + streaming to export-user-data

- Add per-collection row cap (default 10k, env EXPORT_ROW_CAP) via Prisma
  take on all findMany calls
- Add total size cap (default 100MB, env EXPORT_SIZE_CAP_MB); throws
  PayloadTooLargeException (413) when exceeded
- Convert response to Node.js Readable stream piped via NestJS StreamableFile
  to avoid large in-memory buffers
- Export ExportUserDataResult interface (stream + truncated flag) from handler
- Update controller to set Content-Type/Content-Disposition headers and
  return StreamableFile
- Document EXPORT_ROW_CAP and EXPORT_SIZE_CAP_MB env vars in Swagger
- Extend tests: row-cap assertion (take arg), size-cap 413 path, stream assertions

Fixes GOO-223 (M-1 from GOO-200 audit).

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/api/package.json

@@ -17,6 +17,7 @@
     "@aws-sdk/client-s3": "^3.1026.0",
     "@aws-sdk/s3-request-presigner": "^3.1026.0",
     "@goodgo/mcp-servers": "workspace:*",
+    "@goodgo/contracts-events": "workspace:*",
     "@nest-lab/throttler-storage-redis": "^1.2.0",
     "@nestjs/bullmq": "^11.0.4",
     "@nestjs/common": "^11.0.0",