Replace paid flutter_background_geolocation with free flutter_foreground_task

Replace proprietary flutter_background_geolocation (requires paid license
for Android release builds) with free flutter_foreground_task package.
Background location tracking now uses foreground service with periodic
geolocation updates every 30 seconds.

pubspec.lock

@@ -17,14 +17,6 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.13.1"
-  background_fetch:
-    dependency: transitive
-    description:
-      name: background_fetch
-      sha256: a185b471f6ff93c0074e2da98fbdf1e0c5af5a83adb97dfe924a9ef06c9e0175
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.7.0"
   boolean_selector:
     dependency: transitive
     description:
@@ -118,14 +110,14 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
-  flutter_background_geolocation:
+  flutter_foreground_task:
     dependency: "direct main"
     description:
-      name: flutter_background_geolocation
-      sha256: "2c5f23bf35837b31c4e1badadf7fb5da418a1862133b5a671b3e0bfa60c3bf2f"
+      name: flutter_foreground_task
+      sha256: "206017ee1bf864f34b8d7bce664a172717caa21af8da23f55866470dfe316644"
       url: "https://pub.dev"
     source: hosted
-    version: "4.18.3"
+    version: "8.17.0"
   flutter_lints:
     dependency: "direct dev"
     description:
@@ -668,4 +660,4 @@ packages:
     version: "6.6.1"
 sdks:
   dart: ">=3.10.1 <4.0.0"
-  flutter: ">=3.38.0"
+  flutter: ">=3.35.0"