feat: introduce unified agent runtime config and system task prompt framework

- Add structured runtime config files (AGENT_PROFILE.md, AGENT_WORKFLOW.md, AGENT_HOOKS.md, USER_PREFERENCES.md, SYSTEM_TASKS.md, CURRENT_PERSONA.md) for persona, workflow, hooks, and system tasks
- Implement agent_runtime_manager to load, validate, and render runtime config and system task prompts
- Refactor agent initialization to use runtime-managed directories for skills, jobs, memory, and activity logs
- Add AgentHooksMiddleware for structured pre/in/post hooks injection
- Replace hardcoded system task prompts with template-driven rendering from SYSTEM_TASKS.md
- Update tests to cover runtime config loading, migration, and system task prompt rendering
- Update .gitignore to exclude config/agent/

app/agent/middleware/memory.py

@@ -188,7 +188,8 @@ class MemoryMiddleware(AgentMiddleware[MemoryState, ContextT, ResponseT]):  # no
     支持多文件记忆组织：用户可以创建多个 `.md` 文件来按主题组织知识。
 
     参数：
-        memory_dir: 记忆文件目录路径。
+        memory_dir: 记忆文件目录路径。建议使用独立的 `config/agent/memory`
+            目录，避免与 persona/workflow 等根层配置混写。
     """
 
     state_schema = MemoryState
@@ -201,7 +202,7 @@ class MemoryMiddleware(AgentMiddleware[MemoryState, ContextT, ResponseT]):  # no
         """初始化记忆中间件。
 
         参数：
-            memory_dir: 记忆文件目录路径（例如，`"/config/agent"`）。
+            memory_dir: 记忆文件目录路径（例如，`"/config/agent/memory"`）。
                         该目录下所有 `.md` 文件都会被自动加载为记忆。
         """
         self.memory_dir = memory_dir