ci(codeql): Add explicit CodeQL workflow

.github/workflows/codeql.yml

@@ -0,0 +1,55 @@
+name: CodeQL
+
+on:
+  push:
+    branches: ["main"]
+  pull_request:
+    branches: ["main"]
+  schedule:
+    - cron: "23 5 * * 1"
+  workflow_dispatch:
+
+permissions:
+  actions: read
+  contents: read
+  security-events: write
+
+jobs:
+  analyze:
+    name: Analyze (${{ matrix.language }})
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          # This repository contains real source in these languages and CodeQL can
+          # analyze them on GitHub-hosted runners without bespoke build steps.
+          - language: actions
+            build-mode: none
+          - language: go
+            build-mode: autobuild
+          - language: java-kotlin
+            build-mode: none
+          - language: javascript-typescript
+            build-mode: none
+          - language: python
+            build-mode: none
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v5
+
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v4
+        with:
+          languages: ${{ matrix.language }}
+          build-mode: ${{ matrix.build-mode }}
+
+      - name: Autobuild
+        if: matrix.build-mode == 'autobuild'
+        uses: github/codeql-action/autobuild@v4
+
+      - name: Analyze
+        uses: github/codeql-action/analyze@v4
+        with:
+          category: "/language:${{ matrix.language }}"