Add git-bug identity creation step to sync workflow

git-bug requires its own identity (not just git config user.*) before
bridge configuration can work. Add `git-bug user new` step.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: yarikoptic

.github/workflows/sync-git-bug.yml

@@ -38,6 +38,13 @@ jobs:
           chmod +x /usr/local/bin/git-bug
           git-bug version
 
+      - name: Create git-bug identity
+        run: |
+          git-bug user new \
+            --name="github-actions" \
+            --email="github-actions@users.noreply.github.com" \
+            --non-interactive
+
       - name: Configure bridge
         env:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}