Add CodeQL code scanning workflow

Author: Boyeep

.github/workflows/codeql.yml

@@ -0,0 +1,48 @@
+name: CodeQL
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+  schedule:
+    - cron: "18 3 * * 1"
+  workflow_dispatch:
+
+permissions:
+  actions: read
+  contents: read
+  security-events: write
+
+jobs:
+  analyze:
+    name: Analyze (${{ matrix.language }})
+    runs-on: ubuntu-latest
+    timeout-minutes: 45
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - language: javascript-typescript
+            build-mode: none
+          - language: python
+            build-mode: none
+          - language: actions
+            build-mode: none
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v4
+        with:
+          languages: ${{ matrix.language }}
+          build-mode: ${{ matrix.build-mode }}
+
+      - name: Perform CodeQL analysis
+        uses: github/codeql-action/analyze@v4
+        with:
+          category: "/language:${{ matrix.language }}"

README.md

@@ -118,6 +118,8 @@ The root check runs:
 
 `check:workflows` lints `.github/workflows/` with a pinned `actionlint` version via Go.
 
+CodeQL code scanning also runs on GitHub for `javascript-typescript`, `python`, and workflow files.
+
 ## Releases
 
 - Release Drafter keeps a draft release updated from merged pull requests on `main` and can auto-label incoming pull requests by path.

SECURITY.md

@@ -25,5 +25,15 @@ Useful reports include:
 - unsafe upload handling or API behavior
 - secrets exposure in docs, scripts, or CI
 
+## Built-In Scanning
+
+The repository also uses automated scanning to help catch common security issues:
+
+- `gitleaks` in CI for tracked git content
+- CodeQL code scanning on GitHub for JavaScript/TypeScript, Python, and workflow files
+
+Those checks do not replace private disclosure. If you believe a vulnerability is real or
+exploitable, please still report it through a private advisory.
+
 Reports that depend entirely on downstream customizations may still be useful, but they
 may be treated as template hardening suggestions rather than direct vulnerabilities.