Improve Bluetooth handling: permission errors and automatic reconnection

[GlassOnTin]

Summary

• Enhanced error messages when Bluetooth scanning fails due to missing permissions
• Added automatic reconnection with exponential backoff when Bluetooth connections drop
• Implemented connection state tracking for better visibility

Features

1. Enhanced Permission Error Handling

• Detect when user is not in the bluetooth group and provide specific instructions
• Show exact commands for both permanent fix and temporary sudo workaround
• Check permissions proactively before attempting to scan

2. Automatic Reconnection Logic

• Added ConnectionState enum to track connection states (disconnected/connecting/connected/reconnecting)
• Implemented exponential backoff for reconnection attempts (1s → 2s → 4s → ... → 60s max)
• Added comprehensive logging using Python's logging module
• Enhanced error handling to detect specific Bluetooth disconnection errors
• Device continues attempting reconnection until manually stopped

Benefits

This improves reliability when:

• Setting up RadiaCode monitoring for the first time (permission issues)
• Bluetooth connections drop due to:
  • Device timeouts after prolonged streaming (~1-2 minutes)
  • Bluetooth interference
  • Device power cycling
  • Other processes connecting to the device

Changes

• device_reader.py: Added permission checks and automatic reconnection logic
• radiacode/discovery.py: Enhanced BTLEException handling to identify permission-related failures

Example Output

Permission Error:

⚠️  Permission issue detected:
  You are not in the 'bluetooth' group

  To fix this permanently:
    sudo usermod -a -G bluetooth username
    Then logout and login again

  Or run with sudo:
    sudo python device_reader.py

Reconnection:

2025-05-27 00:14:44 - INFO - Connection state: disconnected → connecting
2025-05-27 00:14:44 - INFO - Connecting to Bluetooth 52:43:06:60:13:F2...
2025-05-27 00:14:45 - INFO - Connection state: connecting → connected
2025-05-27 00:14:45 - INFO - ✓ Connected to RC-102-00001234
...
2025-05-27 00:15:12 - ERROR - Bluetooth connection lost
2025-05-27 00:15:12 - INFO - Connection state: connected → disconnected
2025-05-27 00:15:12 - INFO - Connection state: disconnected → reconnecting
2025-05-27 00:15:12 - INFO - Reconnection attempt in 1.0 seconds...
2025-05-27 00:15:13 - INFO - Connection state: reconnecting → connecting
2025-05-27 00:15:14 - INFO - Connection state: connecting → connected
2025-05-27 00:15:14 - INFO - ✓ Connected to RC-102-00001234

Test plan

• [x] Test running without sudo and not in bluetooth group - shows helpful error
• [x] Test running with sudo - works correctly
• [x] Test with user in bluetooth group - provides appropriate guidance
• [x] Test automatic reconnection on connection loss
• [x] Verify exponential backoff working correctly
• [x] Verify connection state logging provides clear visibility

[cdump]

Please rebase your branch to the current master and include only commits related to the description in the PR, you can submit another PR for other changes