feat: 清理 control_node + 引入 task 一等公民

- control_node 标注 DEPRECATED：保留目录壳子供未来远程探针节点复用，删除调用路径与相关测试
- 新增 task 表：极简元数据持久化 regulatory_node 完成的短任务（出报告/写文件/查询整理）
- regulatory_node 自标注：MessageResponse 扩展 task_action/title/summary，_run 末尾非阻塞落库
- query_task_list 改查 task 表，符合用户对"任务列表"的直觉，与 workflow 体系解耦
- 新增 /api/v1/task/list|/{id} 只读 API（task 由 regulatory 内部触发，不开放对外创建）

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/CLAUDE.md

@@ -64,7 +64,7 @@ Mode is set via `KILOSTAR_MODE` env var. Entry point `main.py` branches into `st
 ### Backend Layout (`kilostar/`)
 
 - `api/` — FastAPI routers (auth, chat, agent, workflow, system, resource, platform)
-- `core/individual/` — 4 node types: RegulatoryNode (user-facing QA), ConsciousnessNode (planning), ControlNode (routing), GrowthNode (capability expansion)
+- `core/individual/` — 4 node types: RegulatoryNode (user-facing QA + short tasks), ConsciousnessNode (workflow planning), ControlNode (deprecated; name reserved for future remote-probe node), GrowthNode (capability expansion, not yet implemented)
 - `core/global_state_machine/` — Provider registry, model config state
 - `core/global_workflow_manager/` — Workflow queue & recovery
 - `core/postgres_database/` — DAO layer: `model/` (SQLAlchemy models), `module/` (CRUD methods), `postgres.py` (facade)