build(android): move to Flutter 3.47 template toolchain (Gradle 9.3.1 / AGP 9.1.0 / Kotlin 2.4.0)

The project pinned Gradle 8.12 / AGP 8.9.1 / Kotlin 2.1.0, all three below the
hard error floors that Flutter 3.47.1 enforces in DependencyVersionChecker.kt
(8.14.0 / 8.11.1 / 2.2.20). Nothing here had rotted; the SDK moved.

Targets Flutter's own template defaults rather than the lowest combo that
clears the floors, because Flutter promotes its warn floor to the error floor
in the very next release -- clearing only the hard floor buys one release of
runway. `flutter-android-preflight` on the host re-derives all of this from
the installed SDK.

Also:
- kotlinOptions{} -> kotlin{compilerOptions{}}: the old DSL is a script
  COMPILATION error under Kotlin >= 2.3, not a warning.
- Java/jvmTarget 11 -> 17.
- Drop android.enableJetifier (obsolete, removed outright in AGP 9). Keep the
  migrator's builtInKotlin=false: builtInKotlin=true makes AGP 9.1.0 supply
  Kotlin 2.2.10, BELOW Flutter's own 2.2.20 floor, so Flutter rejects its own
  recommendation.

This app has no native plugins, so it needed none of the pub-plugin
workarounds gps-speedo did.

Verified: flutter build apk --debug and --release, as both mikkeli and hermes.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016dKAqFo9Uj3mPZWvDzj3G8

analysis_options.yaml

@@ -7,6 +7,15 @@
 
 # The following line activates a set of recommended lints for Flutter apps,
 # packages, and plugins designed to encourage good coding practices.
+analyzer:
+  exclude:
+    - build/**
+    - android/**
+    - ios/**
+    - web/**
+    - windows/**
+    - macos/**
+    - linux/**
 include: package:flutter_lints/flutter.yaml
 
 linter:

android/app/build.gradle.kts

@@ -1,3 +1,5 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+
 plugins {
     id("com.android.application")
     id("kotlin-android")
@@ -11,12 +13,8 @@ android {
     ndkVersion = flutter.ndkVersion
 
     compileOptions {
-        sourceCompatibility = JavaVersion.VERSION_11
-        targetCompatibility = JavaVersion.VERSION_11
-    }
-
-    kotlinOptions {
-        jvmTarget = JavaVersion.VERSION_11.toString()
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
     }
 
     defaultConfig {
@@ -39,6 +37,12 @@ android {
     }
 }
 
+kotlin {
+    compilerOptions {
+        jvmTarget.set(JvmTarget.JVM_17)
+    }
+}
+
 flutter {
     source = "../.."
 }

android/gradle.properties

@@ -1,3 +1,6 @@
 org.gradle.jvmargs=-Xmx8G -XX:MaxMetaspaceSize=4G -XX:ReservedCodeCacheSize=512m -XX:+HeapDumpOnOutOfMemoryError
 android.useAndroidX=true
-android.enableJetifier=true
+# This builtInKotlin flag was added automatically by Flutter migrator
+android.builtInKotlin=false
+# This newDsl flag was added automatically by Flutter migrator
+android.newDsl=false

android/gradle/wrapper/gradle-wrapper.properties

@@ -2,4 +2,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.12-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.3.1-all.zip

android/settings.gradle.kts

@@ -19,8 +19,8 @@ pluginManagement {
 
 plugins {
     id("dev.flutter.flutter-plugin-loader") version "1.0.0"
-    id("com.android.application") version "8.9.1" apply false
-    id("org.jetbrains.kotlin.android") version "2.1.0" apply false
+    id("com.android.application") version "9.1.0" apply false
+    id("org.jetbrains.kotlin.android") version "2.4.0" apply false
 }
 
 include(":app")

pubspec.lock

@@ -84,10 +84,10 @@ packages:
     dependency: transitive
     description:
       name: intl
-      sha256: "3df61194eb431efc39c4ceba583b95633a403f46c9fd341e550ce0bfa50e9aa5"
+      sha256: "1ca20c894b1717686a2319b8548763d812bc0aabdac580420a44c5178c57a867"
       url: "https://pub.dev"
     source: hosted
-    version: "0.20.2"
+    version: "0.20.3"
   leak_tracker:
     dependency: transitive
     description:
@@ -124,10 +124,10 @@ packages:
     dependency: transitive
     description:
       name: matcher
-      sha256: dc58c723c3c24bf8d3e2d3ad3f2f9d7bd9cf43ec6feaa64181775e60190153f2
+      sha256: "31bd099b47c10cd1aeb55146a2d46ce0277630ecef3f7dae54ad7873f36696cd"
       url: "https://pub.dev"
     source: hosted
-    version: "0.12.17"
+    version: "0.12.20"
   material_color_utilities:
     dependency: "direct overridden"
     description:
@@ -209,10 +209,10 @@ packages:
     dependency: transitive
     description:
       name: vector_math
-      sha256: d530bd74fea330e6e364cda7a85019c434070188383e1cd8d9777ee586914c5b
+      sha256: f36f9f3be64c6198714492bb455c11056e33e2f85d9a0b676a48301e44fdcf47
       url: "https://pub.dev"
     source: hosted
-    version: "2.2.0"
+    version: "2.4.2"
   vm_service:
     dependency: transitive
     description:
@@ -222,5 +222,5 @@ packages:
     source: hosted
     version: "15.0.2"
 sdks:
-  dart: ">=3.9.0 <4.0.0"
+  dart: ">=3.11.0-0 <4.0.0"
   flutter: ">=3.18.0-18.0.pre.54"