rebrand app from Bocken Fitness to Bocken, track Android project

- Manifest: name/short_name → "Bocken", start_url → "/"
- Tauri: productName → "Bocken", identifier → org.bocken.app, url → "/"
- Cargo: package → bocken, lib → bocken_lib
- Page titles: "- Fitness" → "- Bocken" across all fitness routes
- Build script: auto-regenerate android project on identifier change
- Regenerate app icon from website favicon
- Track Android project source in git (ignore only build output/caches)
- Add native GPS foreground service and AndroidBridge for background
  location tracking (LocationForegroundService, AndroidBridge.kt)
- Add ACCESS_BACKGROUND_LOCATION permission for screen-off GPS

src-tauri/Cargo.toml

@@ -1,10 +1,10 @@
 [package]
-name = "bocken-fitness"
+name = "bocken"
 version = "0.1.0"
 edition = "2021"
 
 [lib]
-name = "bocken_fitness_lib"
+name = "bocken_lib"
 crate-type = ["lib", "cdylib", "staticlib"]
 
 [build-dependencies]