ci(security): add CodeQL and OSV-Scanner workflows

Add static analysis (CodeQL) and dependency vulnerability scanning
(OSV-Scanner) to CI. Both run on push/PR to main and weekly on Monday
08:00 UTC. Results upload to GitHub Security tab via SARIF.

Author: tobyhede

.github/workflows/codeql.yml

@@ -0,0 +1,44 @@
+name: CodeQL
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+  schedule:
+    - cron: "0 8 * * 1"
+
+permissions:
+  security-events: write
+  contents: read
+  actions: read
+
+jobs:
+  analyze:
+    name: Analyze
+    runs-on: blacksmith-4vcpu-ubuntu-2404
+
+    strategy:
+      fail-fast: false
+      matrix:
+        language:
+          - javascript-typescript
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v3
+        with:
+          languages: ${{ matrix.language }}
+
+      - name: Autobuild
+        uses: github/codeql-action/autobuild@v3
+
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@v3
+        with:
+          category: "/language:${{ matrix.language }}"

.github/workflows/osv-scanner.yml

@@ -0,0 +1,25 @@
+name: OSV-Scanner
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+  schedule:
+    - cron: "0 8 * * 1"
+
+permissions:
+  security-events: write
+  contents: read
+  actions: read
+
+jobs:
+  osv-scan:
+    name: OSV Vulnerability Scan
+    uses: google/osv-scanner-action/.github/workflows/osv-scanner-reusable.yml@v2.3.3
+    with:
+      scan-args: |-
+        --recursive
+        ./