Add weekly schedule to CodeQL workflow (#5)

* Add weekly schedule to CodeQL workflow

---------

Co-authored-by: Tao Zhang <zhangt@microsoft.com>

Author: TerrenceZhangX

.github/workflows/codeql.yml

@@ -0,0 +1,36 @@
+name: CodeQL Weekly Scan
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+  schedule:
+    - cron: '0 0 * * 0' # Weekly on Sundays at midnight
+
+jobs:
+  analyze:
+    name: Analyze
+    runs-on: ubuntu-latest
+
+    permissions:
+      actions: read
+      contents: read
+      security-events: write
+
+    strategy:
+      fail-fast: false
+      matrix:
+        language: [ 'python' ]
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v3
+        with:
+          languages: ${{ matrix.language }}
+
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@v3