Clean up Flatpak manifest for v2026.2.0

- Update tag to v2026.2.0
- Use SKIP_WASM_BUILD env var instead of build-time package.json patch
- Install metainfo from git source (remove temporary type: file source)
- Fix fix-lockfile.mjs to skip workspace packages
- CI: commit metainfo releases back to app repo, bump permissions to write

.github/workflows/flathub.yml

@@ -4,7 +4,7 @@ on:
     types: [published]
 
 permissions:
-  contents: read
+  contents: write
 
 jobs:
   update-flathub:
@@ -34,6 +34,15 @@ jobs:
       - name: Run update-manifest.sh
         run: bash flatpak/update-manifest.sh "${{ github.event.release.tag_name }}"
 
+      - name: Commit metainfo update to app repo
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+          git add flatpak/app.yaak.Yaak.metainfo.xml
+          git diff --cached --quiet && echo "No metainfo changes" && exit 0
+          git commit -m "Add ${{ github.event.release.tag_name }} to metainfo releases"
+          git push origin HEAD:main
+
       - name: Checkout Flathub repo
         uses: actions/checkout@v4
         with: