🛂 explicit CI permissions (#515)

Author: jorenham

.github/workflows/ci.yml

@@ -11,6 +11,10 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.sha }}
   cancel-in-progress: true
 
+permissions:
+  contents: read
+  pull-requests: write
+
 env:
   UV_LOCKED: 1