fix(ci): read-only token for Code Quality (#74)

code-quality.yml had no permissions block, so its jobs got the repository default token. None of them writes through GITHUB_TOKEN; permissions: contents: read (CodeQL actions/missing-workflow-permissions #1-#4).

.github/workflows/code-quality.yml

@@ -6,6 +6,11 @@ on:
   pull_request:
     branches: [main]
 
+
+# Read-only token: Code Quality never writes through GITHUB_TOKEN.
+permissions:
+  contents: read
+
 jobs:
   python-lint:
     name: Python Lint