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>

.claude/settings.local.json

@@ -13,7 +13,9 @@
       "Bash(cp:*)",
       "Bash(flutter:*)",
       "Bash(powershell:*)",
-      "WebFetch(domain:docs.anthropic.com)"
+      "WebFetch(domain:docs.anthropic.com)",
+      "WebSearch",
+      "WebFetch(domain:pub.dev)"
     ],
     "defaultMode": "acceptEdits"
   },