ci: Fix duplicate workflow runs

Configure workflow to run on:
- Pushes to main branch only
- All pull requests

This prevents duplicate runs when pushing to PR branches while still
ensuring all commits are validated (either via push to main or PR checks).

Author: claude

.github/workflows/release.yml

@@ -2,6 +2,8 @@ name: Build and Release Addon
 
 on:
   push:
+    branches:
+      - main
   pull_request:
   workflow_dispatch:
     inputs: