feat: agent memory management — CRUD API + Android management screen

Backend:
- New /api/v1/agents/{id}/memory endpoints: CRUD for global_knowledge,
  knowledge_entities, learning_patterns, vector_memories + import/export
- Fix scope_id column overflow: 3 model columns expanded to hold compound
  keys (user_id:agent_id format, 73 chars vs old VARCHAR(36))
- Config: allow unknown env vars (extra="ignore") for optional overrides

Android:
- MemoryManageScreen: 4-tab UI (全局知识/知识实体/学习模式/对话记忆)
  with search, delete, and FAB to add new entries
- Import/export via ShareSheet and file picker
- AgentListScreen: long-press dropdown menu → 记忆管理 entry point
- NavGraph: memory_manage/{agentId}/{agentName} route with URL encoding

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/app/main.py

@@ -510,7 +510,7 @@ async def startup_event():
         logger.error(f"定时任务调度器启动失败: {e}")
 
 # 注册路由
-from app.api import auth, workspaces, uploads, workflows, executions, websocket, execution_logs, data_sources, agents, platform_templates, model_configs, webhooks, template_market, batch_operations, collaboration, permissions, monitoring, alert_rules, node_test, node_templates, tools, agent_chat, agent_branches, agent_monitoring, knowledge_base, knowledge_dashboard, agent_schedules, notifications, feishu_bind, approval, orchestration_templates, plugins, agent_market, goals, tasks, system_logs, audit_logs, feedback, agent_swarm, push, voice, fcm, scene_contracts, teams
+from app.api import auth, workspaces, uploads, workflows, executions, websocket, execution_logs, data_sources, agents, platform_templates, model_configs, webhooks, template_market, batch_operations, collaboration, permissions, monitoring, alert_rules, node_test, node_templates, tools, agent_chat, agent_branches, agent_monitoring, knowledge_base, knowledge_dashboard, agent_schedules, notifications, feishu_bind, approval, orchestration_templates, plugins, agent_market, goals, tasks, system_logs, audit_logs, feedback, agent_swarm, push, voice, fcm, scene_contracts, teams, agent_memory
 
 app.include_router(auth.router)
 app.include_router(workspaces.router)
@@ -556,6 +556,7 @@ app.include_router(fcm.router)
 app.include_router(knowledge_dashboard.router)
 app.include_router(scene_contracts.router)
 app.include_router(teams.router)
+app.include_router(agent_memory.router)
 
 if __name__ == "__main__":
     import uvicorn