fix: audit perbaikan NATS subject, worker spawn, frontend options, pipeline PDF output
Bug fixes:
1. NATS subject doubled prefix — gateway publish ke tools.tools.scan.*
padahal workers subscribe ke tools.scan.*. Fix: pakai group() method
2. Worker subscriptions pake tokio::select! — cuma satu subscription
yang diproses, sisanya di-cancel. Fix: ganti ke tokio::spawn + loop
3. WebSocket URL hardcoded ke localhost:3001 — gak jalan di prod.
Fix: infer dari window.location atau env var
4. Frontend scan options hardcoded — user gak bisa atur OCR/enhance/format.
Fix: interactive toggles, selects, slider
5. Frontend compress quality hardcoded — user gak bisa atur kualitas.
Fix: quality range slider
6. Pipeline cuma output PNG — gak ada PDF/OCR.
Fix: generate searchable PDF kalo tesseract feature enabled
Enhancements:
- Tool::group() method added — returns 'scan', 'image', 'pdf' dll
- Dockerfile: --features tesseract pas cargo build
- leptess OCR: proper API usage (set_image_from_mem, recognize, etc.)
Co-Authored-By: Kilo <kilo@kilo.ai>
