feat: Add PWA support and consolidate CSS design system

- Add PWA manifest, icons (192x192, 512x512), and service worker
- Register service worker in index.html with Apple mobile web app support
- Consolidate CSS variables and design tokens documentation
- Update PrimeVue overrides for consistent theming
- Refactor data-entry components to use shared CSS patterns
- Add frontend-style-auditor agent for style consistency checks
- Minor OCR validation and job worker improvements
- Update start-prod.sh configuration

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/modules/data_entry/services/ocr/job_worker.py

@@ -353,9 +353,9 @@ async def start_job_worker() -> bool:
             logger.info("[JobWorker] Pre-warming OCR worker pool (background)...")
             warmup_success = await ocr_worker_pool.prewarm(timeout=90.0)
             if warmup_success:
-                logger.info("[JobWorker] ✅ OCR worker pool pre-warmed successfully")
+                logger.info("[JobWorker] OCR worker pool pre-warmed successfully")
             else:
-                logger.warning("[JobWorker] ⚠️ Worker pool pre-warm failed, first request will be slower")
+                logger.warning("[JobWorker] Worker pool pre-warm failed, first request will be slower")
 
         asyncio.create_task(_background_prewarm())