feat(aia): Implement Protocol Agent MVP with reusable Agent framework

Sprint 1-3 Completed (Backend + Frontend):

Backend (Sprint 1-2):
- Implement 5-layer Agent framework (Query->Planner->Executor->Tools->Reflection)
- Create agent_schema with 6 tables (agent_definitions, stages, prompts, sessions, traces, reflexion_rules)
- Create protocol_schema with 2 tables (protocol_contexts, protocol_generations)
- Implement Protocol Agent core services (Orchestrator, ContextService, PromptBuilder)
- Integrate LLM service adapter (DeepSeek/Qwen/GPT-5/Claude)
- 6 API endpoints with full authentication
- 10/10 API tests passed

Frontend (Sprint 3):
- Add Protocol Agent entry in AgentHub (indigo theme card)
- Implement ProtocolAgentPage with 3-column layout
- Collapsible sidebar (Gemini style, 48px <-> 280px)
- StatePanel with 5 stage cards (scientific_question, pico, study_design, sample_size, endpoints)
- ChatArea with sync button and action cards integration
- 100% prototype design restoration (608 lines CSS)
- Detailed endpoints structure: baseline, exposure, outcomes, confounders

Features:
- 5-stage dialogue flow for research protocol design
- Conversation-driven interaction with sync-to-protocol button
- Real-time context state management
- One-click protocol generation button (UI ready, backend pending)

Database:
- agent_schema: 6 tables for reusable Agent framework
- protocol_schema: 2 tables for Protocol Agent
- Seed data: 1 agent + 5 stages + 9 prompts + 4 reflexion rules

Code Stats:
- Backend: 13 files, 4338 lines
- Frontend: 14 files, 2071 lines
- Total: 27 files, 6409 lines

Status: MVP core functionality completed, pending frontend-backend integration testing

Next: Sprint 4 - One-click protocol generation + Word export

backend/src/index.ts

@@ -159,6 +159,15 @@ logger.info('✅ PKB个人知识库路由已注册: /api/v1/pkb');
 await fastify.register(aiaRoutes, { prefix: '/api/v1/aia' });
 logger.info('✅ AIA智能问答路由已注册: /api/v1/aia');
 
+// ============================================
+// 【业务模块】Protocol Agent - 研究方案制定Agent
+// ============================================
+import { protocolAgentRoutes } from './modules/agent/protocol/index.js';
+await fastify.register((instance, opts, done) => {
+  protocolAgentRoutes(instance, { prisma, ...opts }).then(() => done()).catch(done);
+}, { prefix: '/api/v1/aia/protocol-agent' });
+logger.info('✅ Protocol Agent路由已注册: /api/v1/aia/protocol-agent');
+
 // ============================================
 // 【业务模块】ASL - AI智能文献筛选
 // ============================================