ci: add CodeQL analysis workflow

.github/workflows/codeql.yml

@@ -0,0 +1,37 @@
+name: CodeQL
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  security-events: write
+
+concurrency:
+  group: codeql-${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  analyze:
+    name: codeql / Python
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v4
+        with:
+          languages: python
+          queries: security-and-quality
+
+      - name: Perform CodeQL analysis
+        uses: github/codeql-action/analyze@v4

CHANGELOG.md

@@ -8,6 +8,7 @@ This project has a published GitHub Release line, but no stable support or API g
 
 ### Added
 
+- Added a dedicated CodeQL workflow for Python code scanning without changing the protected CI required check name.
 - Added a read-only security and supply-chain evaluation record for CodeQL, private vulnerability reporting, Dependabot, Scorecard, and GitHub Actions pinning.
 - Added a non-required Python 3.13 compatibility CI job without changing the protected Python 3.12 required check name.
 - Added a local post-release audit script for repeatable maintainer verification.