v2.2.2: Enhanced background persistence and overlay communication

Major improvements to floating window functionality:
- Implemented lazy overlay listener creation/destruction to eliminate ghost overlay
- Added 2Hz cached GPS data push for smooth overlay updates
- Enhanced background persistence with wake locks and heartbeat mechanisms
- Proper Android foreground functionality using bg_launcher package
- Fixed overlay state management race conditions
- Added comprehensive debug logging throughout communication system
- Improved Android manifest with background persistence permissions
- Eliminated overlay status polling interference with data flow

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

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

pubspec.lock

@@ -25,6 +25,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.13.0"
+  bg_launcher:
+    dependency: "direct main"
+    description:
+      name: bg_launcher
+      sha256: c4c1dfffdcdb2896411a8f2fce8a8fac4712b1664b243b85f69d5347367ea504
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.1.0"
   boolean_selector:
     dependency: transitive
     description: