CI: add least-privilege permissions to GitHub Actions workflows

Add explicit workflow-level permissions blocks to resolve CodeQL
actions/missing-workflow-permissions alerts. Scopes are derived from
workflow operations (git push, artifact upload, Danger, release lanes).

Refs: APPSEC-164

Author: peter-matkovski

.github/workflows/ci.yml

@@ -12,6 +12,12 @@ on:
 
 env:
   BUILD_CACHE_KEY: ${{ github.sha }}-dist
+
+permissions:
+  actions: write
+  contents: read
+  pull-requests: read
+
 jobs:
   lint:
     runs-on: ubuntu-latest