Add structured logging, navigation bar, and code cleanup

## Backend
- Add Pino logging framework with timestamps and structured output
- Replace all console.error statements (49+) with proper logging levels
- Fix Drizzle ORM bug: replace invalid .get() calls with .limit(1)
- Remove unused auth routes file (already in index.js)
- Make internal functions private (remove unnecessary exports)
- Simplify code by removing excessive debug logging

## Frontend
- Add navigation bar to layout with:
  - User's callsign display
  - Navigation links (Dashboard, QSOs, Settings)
  - Logout button with red color distinction
- Navigation only shows when user is logged in
- Dark themed design matching footer

## Documentation
- Update README.md with new project structure
- Update docs/DOCUMENTATION.md with logging and nav bar info
- Add logger.js to configuration section

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

package.json

@@ -24,6 +24,8 @@
     "@elysiajs/static": "^1.4.7",
     "bcrypt": "^6.0.0",
     "drizzle-orm": "^0.45.1",
-    "elysia": "^1.4.22"
+    "elysia": "^1.4.22",
+    "pino": "^10.2.0",
+    "pino-pretty": "^13.1.3"
   }
 }