ci(release): grant contents:write to the release workflow (#16)

The workflow creates a GitHub release and uploads assets, which needs the contents:write token scope. Declaring it per-workflow (matching release-launcher.yml on main) lets the repo keep a read-only default GITHUB_TOKEN.

.github/workflows/release.yml

@@ -11,6 +11,9 @@ on:
     tags:
       - 'v1-december-*'
 
+permissions:
+  contents: write   # create the GitHub release + upload assets
+
 jobs:
   release:
     runs-on: windows-latest