Add Debug page and fix BLE communication issues

Major changes:
- Added Debug tab with real-time message logging and hex viewer
- Implemented timed data logging ($UMTDL command) per API v1.3
- Fixed BLE message parsing to handle notifications without line endings
- Added Schema 2 support (22-field timed logging packets)
- Updated Maglink BLE UUIDs (fff0/fff1/fff2)
- Added connection timeout (10s) to prevent hanging on unavailable devices
- Added connection status display and manual push-button logging trigger
- Improved retry logging with attempt numbers and delays
- Added console window allocation for Windows debug output
- Added BLE disconnect on app close

Bug fixes:
- Fixed device name filtering for Maglink (ML-* prefix)
- Fixed RtkGps enum reference in DeviceScanViewModel
- Fixed DebugMessage namespace (moved to Models)

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

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

README.md

@@ -4,6 +4,8 @@ Cross-platform .NET MAUI app (Windows, macOS, iOS, Android) for logging utility
 points from an **Underground Magnetics locating receiver** paired with RTK GPS positions
 from a **Maglink (H11) RTK receiver**, both over BLE.
 
+Maps API Key: AIzaSyDhH16gF-7UN-CBsTQGfQSHNGjLC6VJ5dI
+
 ## Solution layout
 
 ```