Backend: POST /api/v1/tools/:toolId/batch accepts multiple files +
settings, processes via p-queue with CONCURRENT_JOBS concurrency limit,
streams ZIP response using archiver. Tool registry in tool-factory
enables batch to reuse any registered tool's process function. SSE
endpoint at GET /api/v1/jobs/:jobId/progress provides real-time updates.
Handles partial failures gracefully, preserves filenames, deduplicates
collisions. Frontend: use-batch-processor hook handles upload, SSE
progress tracking, and automatic ZIP download.
- Register @fastify/multipart plugin with size limits from env config
- Workspace manager: createWorkspace, getWorkspacePath, cleanupWorkspace
- File validation: magic byte detection, format check, megapixel limit
- POST /api/v1/upload: multipart upload with validation, returns jobId + file metadata
- GET /api/v1/download/:jobId/:filename: serve files with Content-Disposition
- Path traversal guards on all file-serving endpoints
- Add @stirling-image/image-engine and sharp as API dependencies
- Add apiUpload, getDownloadUrl, apiDownloadBlob to web client