ci: nightly catch-up bump of the cinny submodule (matrix #9)

Pairs with cinny's debounced trigger-desktop job: commits that land inside
the one-hour debounce window reach a desktop build here (04:00 UTC daily,
or on manual dispatch).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

.gitea/workflows/catch-up.yml

@@ -0,0 +1,35 @@
+name: Catch up cinny submodule
+
+# [matrix #9] cinny's CI only bumps the submodule at most once an hour (its
+# trigger-desktop job is debounced), so web commits that land inside that
+# window would otherwise never reach a desktop build. This nightly run (or a
+# manual dispatch) moves the submodule to cinny's current `lotus` HEAD; the
+# resulting push starts release.yml as usual. No-op when already current.
+on:
+  schedule:
+    - cron: '0 4 * * *'
+  workflow_dispatch:
+
+jobs:
+  catch-up:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Bump cinny submodule to lotus HEAD
+        env:
+          TOKEN: ${{ secrets.RELEASE_TOKEN }}
+        run: |
+          git clone "https://x-access-token:$TOKEN@code.lotusguild.org/LotusGuild/cinny-desktop.git" desktop
+          cd desktop
+          git config user.email "ci@lotusguild.org"
+          git config user.name "Lotus CI"
+          git submodule update --init cinny
+          git -C cinny fetch origin lotus
+          git -C cinny checkout origin/lotus
+          git add cinny
+          if git diff --cached --quiet; then
+            echo "Submodule already at lotus HEAD, nothing to do"
+          else
+            SHA=$(git -C cinny rev-parse HEAD)
+            git commit -m "chore: bump cinny submodule to ${SHA:0:8} (nightly catch-up)"
+            git push origin main
+          fi