feat: add debug page with tables and logs viewer (Step 1)

Backend:
- Add /debug/tables endpoint to dump SQLite tables
- Add /debug/logs endpoint to read scrap.log

Frontend:
- Add react-router-dom for navigation
- Create HomePage and DebugPage components
- Add navigation bar with Debug link
- Style debug page with Gruvbox theme
- Fix package.json dependencies versions

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

backend/app/api/__init__.py

@@ -1,10 +1,12 @@
 """Module routers."""
 from .routes_config import router as config_router
+from .routes_debug import router as debug_router
 from .routes_products import router as products_router
 from .routes_scrape import router as scrape_router
 
 __all__ = [
     "config_router",
+    "debug_router",
     "products_router",
     "scrape_router",
 ]