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/app/agent_runtime/core.py

@@ -126,6 +126,7 @@ class AgentRuntime:
             team_share_enabled=self.config.memory.team_share_enabled,
             memory_dir_enabled=self.config.memory.memory_dir_enabled,
             memory_dir_path=self.config.memory.memory_dir_path,
+            parent_agent_id=self.config.memory.parent_agent_id,
         )
         self.tool_manager = tool_manager or AgentToolManager(
             include_tools=self.config.tools.include_tools,
@@ -1821,8 +1822,17 @@ class _LLMClient:
                 except Exception as ce:
                     logger.error("ReactiveCompact 失败: %s", ce)
 
-            # 降级回退：主模型失败时尝试 fallback_llm
+            # 降级回退：主模型失败时尝试 fallback_llm（优先每 Agent 配置，其次全局配置）
             fallback = self._config.fallback_llm
+            if not fallback:
+                # 全局降级配置兜底
+                fb_model = settings.FALLBACK_LLM_MODEL
+                if fb_model:
+                    fallback = {
+                        "model": fb_model,
+                        "api_key": settings.FALLBACK_LLM_API_KEY or None,
+                        "base_url": settings.FALLBACK_LLM_BASE_URL or None,
+                    }
             if fallback and isinstance(fallback, dict) and not _is_fallback:
                 fb_model = fallback.get("model")
                 fb_api_key = fallback.get("api_key")