Refactor Android CI workflow to use Nix actions and improve translation file collection

.github/workflows/android.yaml

@@ -11,28 +11,30 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - name: Install Nix (for nix usage)
-        run: |
-          set -euo pipefail
-          curl -L https://nixos.org/nix/install | sh -s -- --no-daemon
-          . "$HOME/.nix-profile/etc/profile.d/nix.sh"
-          nix --version
-
       - name: Checkout code
         uses: actions/checkout@v6
 
+      - name: Prepare Nix devshell
+        uses: ./.github/actions/nix-devshell
+        with:
+          prebuild: "true"
+
       - name: Collect Translation Files
-        run: |
-          set -euo pipefail
-          . "$HOME/.nix-profile/etc/profile.d/nix.sh"
-          nix --version
-          cd lib/l10n
-          nix --extra-experimental-features 'nix-command flakes' develop --command python3 collect_translations.py
-          cd ../..
+        uses: ./.github/actions/nix-devshell
+        with:
+          commands: |
+            cd lib/l10n
+            python3 collect_translations.py
 
       - name: Build Debug APK
-        run: |
-          set -euo pipefail
-          . "$HOME/.nix-profile/etc/profile.d/nix.sh"
-          nix --version
-          nix --extra-experimental-features 'nix-command flakes' develop --command flutter build apk --debug
+        uses: ./.github/actions/nix-devshell
+        with:
+          commands: |
+            flutter build apk --debug --target-platform android-arm64
+
+      - name: Upload APK artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: app-debug-apk
+          path: build/app/outputs/flutter-apk/*.apk
+          # retention-days: 90