Fix release workflow failing when version already matches

The "Commit and push version bump" step hard-failed (exit 1) when
plugin.json and marketplace.json already contained the target version,
preventing the tag and GitHub release from being created. Treat an
already-correct version as a no-op and proceed to tagging.

.github/workflows/release.yml

@@ -73,8 +73,8 @@ jobs:
         run: |
           set -euo pipefail
           if git diff --quiet .claude-plugin/plugin.json .claude-plugin/marketplace.json; then
-            echo "No version change detected."
-            exit 1
+            echo "Version already set to $VERSION. Skipping commit."
+            exit 0
           fi
           git config user.name "github-actions[bot]"
           git config user.email "41898282+github-actions[bot]@users.noreply.github.com"