fix: install Android SDK in build-apk CI job

The build-apk job was failing because the Docker runner image
doesn't include Android SDK. Added steps to download Android
command-line tools, accept licenses, and install SDK 34.

.gitea/workflows/ci.yml

@@ -42,7 +42,7 @@ jobs:
 
     steps:
       - name: Install system dependencies
-        run: apt-get update && apt-get install -y jq unzip xz-utils curl git
+        run: apt-get update && apt-get install -y jq unzip xz-utils curl git wget
 
       - name: Checkout
         uses: actions/checkout@v4
@@ -53,6 +53,24 @@ jobs:
           distribution: temurin
           java-version: 17
 
+      - name: Setup Android SDK
+        run: |
+          mkdir -p /opt/android-sdk/cmdline-tools
+          cd /tmp
+          wget -q "https://dl.google.com/android/repository/commandlinetools-linux-11076708_latest.zip" -O cmdline-tools.zip
+          unzip -q cmdline-tools.zip
+          mv cmdline-tools /opt/android-sdk/cmdline-tools/latest
+          echo "ANDROID_HOME=/opt/android-sdk" >> $GITHUB_ENV
+          echo "ANDROID_SDK_ROOT=/opt/android-sdk" >> $GITHUB_ENV
+          echo "/opt/android-sdk/cmdline-tools/latest/bin" >> $GITHUB_PATH
+          echo "/opt/android-sdk/platform-tools" >> $GITHUB_PATH
+
+      - name: Accept Android licenses and install SDK components
+        run: |
+          export ANDROID_HOME=/opt/android-sdk
+          yes | /opt/android-sdk/cmdline-tools/latest/bin/sdkmanager --licenses || true
+          /opt/android-sdk/cmdline-tools/latest/bin/sdkmanager "platforms;android-34" "build-tools;34.0.0" "platform-tools"
+
       - name: Setup Flutter
         uses: subosito/flutter-action@v2
         with: