chore: import upstream snapshot with attribution

.github/workflows/codeql.yml

@@ -0,0 +1,56 @@
+name: CodeQL
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+# Cancel a superseded run for the same ref (e.g. a force-push to a PR) so we
+# don't burn CI minutes analyzing commits that are already stale.
+concurrency:
+  group: codeql-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  analyze:
+    name: Analyze (${{ matrix.language }})
+    runs-on: ubuntu-latest
+    timeout-minutes: 360
+    permissions:
+      # Required to upload code-scanning results to the Security tab.
+      security-events: write
+      # Required by codeql-action to read the workflow/CI config.
+      actions: read
+      contents: read
+
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          # Haystack is a Python project; Python is interpreted, so no build is
+          # needed. Add `javascript-typescript` here if the docs-website JS code
+          # should also be scanned.
+          - language: python
+            build-mode: none
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          persist-credentials: false
+
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@99df26d4f13ea111d4ec1a7dddef6063f76b97e9 # v4.37.0
+        with:
+          languages: ${{ matrix.language }}
+          build-mode: ${{ matrix.build-mode }}
+
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@99df26d4f13ea111d4ec1a7dddef6063f76b97e9 # v4.37.0
+        with:
+          category: "/language:${{ matrix.language }}"