Migrate fires_flutter to flutter_map v6.1.0 and complete major null-safety fixes

- Updated Android build files: gradle plugin 8.2.2, gradle 8.3, SDK 34, minSdk 21
- Ran dart fix --apply for 87 automatic null-safety fixes
- Migrated flutter_map v6 API breaking changes:
  - MapOptions: center → initialCenter, zoom → initialZoom
  - layers → children structure
  - TileLayerOptions/MarkerLayerOptions/PolylineLayerOptions → TileLayer/MarkerLayer/PolylineLayer
  - Removed plugin_api.dart imports
  - Converted old plugin system (ZoomMapPlugin, AttributionPlugin, etc.) to direct widgets
  - Updated onTap callback signature: (TapPosition) → (TapPosition, LatLng)
- Migrated all marker/polyline creation to v6 API
- Fixed FlatButton → TextButton deprecation
- Fixed stackTrace access with catch(e, stackTrace) pattern
- Removed deprecated flutter_google_places_autocomplete dependency
- Removed deprecated dependencies: latlong, connectivity, launch_review
- Updated all imports from latlong → latlong2
- Placeholder implementation for places autocomplete (feature temporarily disabled)

Remaining tasks (non-blocking for build):
- Complete null-safety fixes for _location variables in genericMap.dart
- Fix theme.dart MaterialTheme parameter issues
- Fix customStepper.dart null-safety issues
- Final build and testing

android/app/build.gradle

@@ -19,7 +19,8 @@ def keystoreProperties = new Properties()
 keystoreProperties.load(new FileInputStream(keystorePropertiesFile))
 
 android {
-    compileSdkVersion 30
+    compileSdkVersion 34
+    namespace "org.comunes.fires"
 
     lintOptions {
         disable 'InvalidPackage'
@@ -28,8 +29,8 @@ android {
     defaultConfig {
         // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
         applicationId "org.comunes.fires"
-        minSdkVersion 16
-        targetSdkVersion 30
+        minSdkVersion 21
+        targetSdkVersion 34
         versionCode 9
         versionName "1.9"
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
@@ -75,9 +76,10 @@ flutter {
 }
 
 dependencies {
-    testImplementation 'junit:junit:4.12'
-    androidTestImplementation 'com.android.support.test:runner:1.0.1'
-    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
+    testImplementation 'junit:junit:4.13.2'
+    // androidx test dependencies replace old android.support.test
+    androidTestImplementation 'androidx.test:runner:1.5.2'
+    androidTestImplementation 'androidx.test.espresso:espresso-core:3.5.1'
     // implementation 'com.google.firebase:firebase-core:15.0.2'
     // google recommends 16 but fails because location flutter package deps in 15
 }

android/build.gradle

@@ -5,7 +5,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.1.0'
+        classpath 'com.android.tools.build:gradle:8.2.2'
         classpath 'com.google.gms:google-services:4.3.4'
     }
 }

android/gradle/wrapper/gradle-wrapper.properties

@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.7-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.3-all.zip