feat: add GitHub Actions workflows for PR checks and security scans

.github/workflows/security-scan.yml

@@ -0,0 +1,46 @@
+name: Security Scan
+
+on:
+  pull_request:
+    branches:
+      - main
+      - beta
+      - dev
+
+permissions:
+  contents: read
+
+jobs:
+  security-checks:
+    name: Security & Dependencies
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+          cache: 'pip'
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -r requirements.txt
+          pip install bandit safety
+
+      - name: Bandit security check
+        run: |
+          bandit -r src/ -f json -o bandit-report.json || true
+          bandit -r src/ -f txt
+
+      - name: Safety check for dependencies
+        run: safety check --json || true
+
+      - name: Trivy vulnerability scan
+        uses: aquasecurity/trivy-action@master
+        with:
+          scan-type: 'fs'
+          scan-ref: '.'
+          format: 'table'
+          severity: 'CRITICAL,HIGH'
+          exit-code: '1'