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>

frontend/package.json

@@ -10,13 +10,14 @@
   "dependencies": {
     "react": "^18.3.1",
     "react-dom": "^18.3.1",
+    "react-router-dom": "^6.22.0",
     "chart.js": "^4.4.0",
     "zustand": "^4.4.0",
-    "@fortawesome/fontawesome-free": "^7.2.0"
+    "@fortawesome/fontawesome-free": "^6.5.0"
   },
   "devDependencies": {
     "vite": "^5.1.3",
     "@vitejs/plugin-react": "^4.0.0",
-    "sass": "^2.0.0"
+    "sass": "^1.77.0"
   }
 }