fix: delete agent 500 error + dynamic personality + deployment guide

- Fix delete agent 500: clean up FK records (agent_llm_logs, permissions,
  schedules, executions, team_members) and unbind goals/tasks before delete
- Remove hardcoded personality templates in Android, replace with dynamic
  system prompt generation from name + description
- Set promptSectionsEnabled=false to bypass PromptComposer for personality
- Add Tencent Cloud Linux deployment guide (Docker Compose)
- Accumulated backend service updates, frontend UI fixes, Android app changes

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.github/workflows/security.yml

@@ -0,0 +1,90 @@
+name: Security Scan
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+  schedule:
+    - cron: "0 8 * * 1" # Run every Monday at 08:00 UTC
+
+jobs:
+  # ============================================================
+  # CodeQL — static analysis for Python + JavaScript/TypeScript
+  # ============================================================
+  codeql:
+    runs-on: ubuntu-latest
+    permissions:
+      security-events: write
+      actions: read
+      contents: read
+
+    strategy:
+      fail-fast: false
+      matrix:
+        language: [python, javascript-typescript]
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@v3
+        with:
+          languages: ${{ matrix.language }}
+
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@v3
+        with:
+          category: "/language:${{ matrix.language }}"
+
+  # ============================================================
+  # Dependency review — check for known vulnerabilities
+  # ============================================================
+  dependency-review:
+    runs-on: ubuntu-latest
+    if: github.event_name == 'pull_request'
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Dependency Review
+        uses: actions/dependency-review-action@v4
+        with:
+          fail-on-severity: high
+
+  # ============================================================
+  # Trivy — scan Docker image for vulnerabilities
+  # ============================================================
+  trivy-backend:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Build backend image
+        run: docker build -t aiagent-backend:scan ./backend
+
+      - name: Run Trivy vulnerability scanner
+        uses: aquasecurity/trivy-action@master
+        with:
+          image-ref: aiagent-backend:scan
+          format: sarif
+          output: trivy-backend.sarif
+          severity: "HIGH,CRITICAL"
+
+      - name: Upload Trivy results
+        uses: github/codeql-action/upload-sarif@v3
+        if: always()
+        with:
+          sarif_file: trivy-backend.sarif
+
+  # ============================================================
+  # Secret scanning — detect hardcoded secrets
+  # ============================================================
+  secret-scan:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Gitleaks — scan for secrets
+        uses: gitleaks/gitleaks-action@v2
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}