Attach APK to matching GitHub Release for production tag builds

When the Android workflow is dispatched against a tag (which is how our
Releases are cut) with the production profile, attach the signed universal
APK to the matching GitHub Release as Bluesky-<version>.apk.

Runs as a separate attachToRelease job so that contents: write is isolated
there and the build job stays read-only. Only attaches to a release that
already exists — never creates one — and pings Slack on success.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.github/workflows/build-submit-android.yml

@@ -23,6 +23,9 @@ jobs:
     concurrency:
       group: android-build
       cancel-in-progress: false
+    outputs:
+      package-version: ${{ steps.get-build-info.outputs.PACKAGE_VERSION }}
+      apk-artifact-name: build-${{ steps.timestamp.outputs.time }}.apk
     steps:
       - name: Check for EXPO_TOKEN
         run: >
@@ -177,3 +180,62 @@ jobs:
         env:
           GITHUB_SHA: ${{ github.sha }}
         run: echo $GITHUB_SHA > most-recent-testflight-commit.txt
+
+  # Releases are cut from tags named after the version (e.g. "1.124.0"), so when a production
+  # build is dispatched against such a tag we attach the APK to the matching release. This runs
+  # as a separate job so that `contents: write` is isolated here and the build job stays read-only.
+  attachToRelease:
+    name: Attach APK to GitHub Release
+    runs-on: ubuntu-latest
+    needs: [build]
+    if: ${{ inputs.profile == 'production' && github.ref_type == 'tag' && github.repository == 'bluesky-social/social-app' }}
+    permissions:
+      contents: write
+    steps:
+      # We only attach to a release that already exists — never create one.
+      - name: 🔎 Check for matching GitHub Release
+        id: release-check
+        env:
+          GH_TOKEN: ${{ github.token }}
+          TAG: ${{ github.ref_name }}
+        run: |
+          status=$(curl -sS -o /dev/null -w '%{http_code}' \
+            -H "Authorization: Bearer $GH_TOKEN" \
+            -H "Accept: application/vnd.github+json" \
+            "${GITHUB_API_URL}/repos/${GITHUB_REPOSITORY}/releases/tags/${TAG}")
+          if [ "$status" = "200" ]; then
+            echo "Found GitHub Release for tag $TAG"
+            echo "exists=true" >> "$GITHUB_OUTPUT"
+          else
+            echo "No GitHub Release found for tag $TAG (HTTP $status); skipping APK attachment."
+            echo "exists=false" >> "$GITHUB_OUTPUT"
+          fi
+
+      - name: ⬇️ Download APK artifact
+        if: ${{ steps.release-check.outputs.exists == 'true' }}
+        uses: actions/download-artifact@37930b1c2abaa49bbe596cd826c3c89aef350131 # v7.0.0
+        with:
+          name: ${{ needs.build.outputs.apk-artifact-name }}
+
+      - name: 🏷️ Rename APK for release
+        if: ${{ steps.release-check.outputs.exists == 'true' }}
+        run: cp build.apk "Bluesky-${{ needs.build.outputs.package-version }}.apk"
+
+      - name: 📎 Attach APK to GitHub Release
+        id: attach
+        if: ${{ steps.release-check.outputs.exists == 'true' }}
+        uses: softprops/action-gh-release@b4309332981a82ec1c5618f44dd2e27cc8bfbfda # v3.0.0
+        with:
+          tag_name: ${{ github.ref_name }}
+          files: Bluesky-${{ needs.build.outputs.package-version }}.apk
+          fail_on_unmatched_files: true
+
+      - name: 🔔 Notify Slack of Release Attachment
+        if: ${{ steps.release-check.outputs.exists == 'true' }}
+        uses: slackapi/slack-github-action@45a88b9581bfab2566dc881e2cd66d334e621e2c # v3.0.3
+        with:
+          webhook: ${{ secrets.SLACK_CLIENT_ALERT_WEBHOOK }}
+          webhook-type: incoming-webhook
+          payload-templated: true
+          payload: |
+            {"text": "Android APK attached to GitHub Release ${{ github.ref_name }}!\n```Asset: Bluesky-${{ needs.build.outputs.package-version }}.apk\nRelease: ${{ steps.attach.outputs.url }}```"}