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>

.demo_memory/feedback_testing.md

@@ -0,0 +1,9 @@
+---
+description: 集成测试必须使用真实数据库而非 mock，因为 mock 与生产环境不一致曾导致故障
+name: '测试规范: 集成测试用真实数据库'
+type: feedback
+---
+
+集成测试必须使用真实数据库，不要 mock。
+Why: 2026年3月有一次生产迁移失败，因为mock测试通过但真实schema不兼容。
+How to apply: 所有涉及 SQLAlchemy session 的测试用例必须使用测试数据库。