Backend:
- Filter out CID=0 and MCC=0 entries (ARFCNs with no decoded cell identity)
Frontend:
- Move stats update before coordinate check so towers always counted
- Fix signal_strength display using null check instead of || (0 is falsy)
- Show operator name, frequency, and status in tower detail panel
- Show "Located" indicator in tower list for geocoded towers
- Fix selectTower crash when tower has no coordinates
- Update placeholder text to "Select a tower from the list"
- Add try/catch to selectTower for error resilience
Tests:
- Add tests for CID=0 and MCC=0 filtering
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>