v2.1.0: Add floating window overlay functionality

Major Features:
- Floating overlay window with system-level persistence
- Split decimal display (main speed prominent, decimal smaller/faded)
- Optimized content sizing for maximum readability
- Navigation icon trigger for overlay activation
- Multiple close options (overlay button + long-press navigation)

Technical Implementation:
- Added flutter_overlay_window dependency
- Android SYSTEM_ALERT_WINDOW permissions
- Overlay service configuration in AndroidManifest
- Enhanced flex ratios for better space utilization
- BoxFit.contain for improved content scaling

UX Improvements:
- Streamlined overlay launch (removed permission prompts)
- Cleaner visual hierarchy with split speed display
- Responsive design for both portrait and landscape
- Professional overlay styling matching app theme

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

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

pubspec.yaml

@@ -2,7 +2,7 @@ name: gps_speedo
 description: "Speedo - A Flutter application."
 publish_to: 'none'
 
-version: 2.0.0+1
+version: 2.1.0+2
 
 environment:
   sdk: ^3.9.0
@@ -20,6 +20,9 @@ dependencies:
   
   # Keep screen awake during navigation
   wakelock_plus: ^1.2.8
+  
+  # Floating window overlay capability
+  flutter_overlay_window: ^0.5.0
 
 
 dev_dependencies: