Add HTTP print API for packing list and sign-off receipt

- core/printing.py: SumatraPDF silent print backend (dry_run, timeout, error capture)
- core/print_document.py: orchestrate generate() + print, per-report paper size, printer fallback
- core/print_api.py: FastAPI POST /api/print + GET /api/health, HTTPBearer auth, English Swagger at /api/docs
- serve.py: uvicorn entrypoint
- config: printers/print/api sections in settings.yaml + core/settings.py
- requirements.txt: add fastapi, uvicorn
- .gitignore: ignore logs/

.gitignore

@@ -13,7 +13,7 @@ config/settings.yaml
 
 # generated output
 out/
-
+logs/
 # verification artifacts
 *.preview.png
 _smoke_*