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>

backend/data/init_database.sql

@@ -0,0 +1,10 @@
+-- 初始化数据库脚本
+-- 需要在MySQL中先创建数据库
+
+-- 创建数据库（如果不存在）
+CREATE DATABASE IF NOT EXISTS agent_db CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
+
+-- 使用数据库
+USE agent_db;
+
+-- 注意：表结构会通过SQLAlchemy自动创建，或者使用Alembic迁移