ci: introduce manual Azure Pipelines Android pilot (#44)

* ci: add manual nonpublishing Azure Android pipeline pilot

* ci(azure): reclaim hosted runner disk and bound Gradle resources

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Co-authored-by: Developer <dev@example.com>

azure-pipelines.yml

@@ -0,0 +1,79 @@
+# MotorSignal Azure Pipelines pilot
+# Manual, non-publishing validation only. No signing keys or deployments.
+trigger: none
+pr: none
+
+pool:
+  vmImage: ubuntu-24.04
+
+variables:
+  flutterVersion: '3.44.6'
+
+steps:
+  - checkout: self
+    clean: true
+    fetchDepth: 1
+
+  - bash: |
+      set -euo pipefail
+      echo 'Before cleanup:'
+      df -h /
+      free -h
+      # Microsoft-hosted Ubuntu includes toolchains this Android pipeline does not need.
+      sudo rm -rf /usr/share/dotnet /usr/local/share/powershell /opt/ghc /usr/local/.ghcup
+      sudo rm -rf /usr/local/lib/android/sdk/emulator /usr/local/lib/android/sdk/system-images
+      sudo apt-get clean
+      echo 'After cleanup:'
+      df -h /
+      free -h
+      available_kb="$(df --output=avail / | tail -1 | tr -d ' ')"
+      if [ "$available_kb" -lt 6291456 ]; then
+        echo 'At least 6 GiB free disk is required before Android SDK provisioning.'
+        exit 1
+      fi
+    displayName: 'Free unused toolchains and verify disk capacity'
+
+  - bash: |
+      set -euo pipefail
+      git clone --depth 1 --branch "$(flutterVersion)" https://github.com/flutter/flutter.git "$(Agent.TempDirectory)/flutter"
+      echo "##vso[task.prependpath]$(Agent.TempDirectory)/flutter/bin"
+      "$(Agent.TempDirectory)/flutter/bin/flutter" --version
+    displayName: 'Install pinned Flutter SDK'
+
+  - bash: |
+      set -euo pipefail
+      flutter pub get
+      dart run build_runner build --delete-conflicting-outputs
+      flutter analyze --no-fatal-infos
+      flutter test
+    displayName: 'Generate, analyze and test Flutter'
+
+  - bash: |
+      set -euo pipefail
+      echo 'Before Android compilation:'
+      df -h /
+      free -h
+      SDKROOT="${ANDROID_SDK_ROOT:-${ANDROID_HOME:-}}"
+      test -n "$SDKROOT"
+      echo "flutter.sdk=$(Agent.TempDirectory)/flutter" > android/local.properties
+      SDKMANAGER="$(find "$SDKROOT/cmdline-tools" -type f -name sdkmanager -print -quit 2>/dev/null || true)"
+      test -x "$SDKMANAGER"
+      "$SDKMANAGER" 'platforms;android-36' 'build-tools;36.0.0' 'platform-tools'
+      if [ ! -f android/gradlew ]; then
+        (cd android && gradle wrapper --gradle-version 9.1.0 --distribution-type all)
+      fi
+      chmod +x android/gradlew
+      # Agent-specific limits, applied only in CI's disposable checkout.
+      cat >> android/gradle.properties <<'GRADLE_LIMITS'
+      org.gradle.jvmargs=-Xmx2g -XX:MaxMetaspaceSize=768m -XX:ReservedCodeCacheSize=256m -Dfile.encoding=UTF-8
+      org.gradle.workers.max=2
+      org.gradle.parallel=false
+      org.gradle.daemon=false
+      GRADLE_LIMITS
+      export JAVA_TOOL_OPTIONS="-XX:MaxRAMPercentage=60"
+      flutter build apk --debug
+      test -s build/app/outputs/flutter-apk/app-debug.apk || test -s build/app/outputs/flutter-apk/app-production-debug.apk
+      echo 'Android debug APK built and verified locally; artifact intentionally not published.'
+      df -h /
+      free -h
+    displayName: 'Build and verify debug APK without artifact upload'