Add security scan workflow using Gitleaks

This workflow runs a security scan using Gitleaks on pushes and pull requests to the main branch, as well as on a scheduled basis every Monday.

Author: Nuclear-Peacock

.github/workflows/security.yml

@@ -0,0 +1,26 @@
+name: "Security Shield"
+
+on:
+  push:
+    branches: ["main"]
+  pull_request:
+    branches: ["main"]
+  schedule:
+    - cron: '0 0 * * 1' # Runs every Monday at midnight
+  workflow_dispatch:      # Allows manual trigger
+
+jobs:
+  scan:
+    name: Security Scan
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      security-events: write
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+      - name: Run Gitleaks
+        uses: gitleaks/gitleaks-action@v2
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}