fix(release): handle manual workflow runs gracefully

The release job failed when triggered manually because action-gh-release
requires a tag. Extract versionName from build.gradle.kts, upload the APK
as a workflow artifact on workflow_dispatch, and only publish to GitHub
Releases on tag pushes.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: nichu42

.github/workflows/release.yml

@@ -39,12 +39,26 @@ jobs:
           chmod +x ./gradlew
           ./gradlew assembleRelease --no-daemon -Dorg.gradle.jvmargs="-Xmx2048m" -Dorg.gradle.workers.max=2 --warning-mode all
 
+      - name: Extract version name
+        id: version
+        run: |
+          version=$(sed -n 's/.*versionName = "\([^"]*\)".*/\1/p' app/build.gradle.kts)
+          echo "version=$version" >> "$GITHUB_OUTPUT"
+
       - name: Rename release APK
-        run: cp app/build/outputs/apk/release/app-release.apk "BoxViewer-${{ github.ref_name }}.apk"
+        run: cp app/build/outputs/apk/release/app-release.apk "BoxViewer-${{ steps.version.outputs.version }}.apk"
+
+      - name: Upload APK artifact for manual runs
+        if: github.event_name == 'workflow_dispatch'
+        uses: actions/upload-artifact@v4
+        with:
+          name: BoxViewer-${{ steps.version.outputs.version }}
+          path: BoxViewer-${{ steps.version.outputs.version }}.apk
 
       - name: Upload release APK to GitHub Releases
+        if: startsWith(github.ref, 'refs/tags/v')
         uses: softprops/action-gh-release@v2
         with:
           name: ${{ github.ref_name }}
-          files: BoxViewer-${{ github.ref_name }}.apk
+          files: BoxViewer-${{ steps.version.outputs.version }}.apk
           generate_release_notes: true