feat(pkb): Complete PKB module frontend migration with V3 design

Summary:
- Implement PKB Dashboard and Workspace pages based on V3 prototype
- Add single-layer header with integrated Tab navigation
- Implement 3 work modes: Full Text, Deep Read, Batch Processing
- Integrate Ant Design X Chat component for AI conversations
- Create BatchModeComplete with template selection and document processing
- Add compact work mode selector with dropdown design

Backend:
- Migrate PKB controllers and services to /modules/pkb structure
- Register v2 API routes at /api/v2/pkb/knowledge
- Maintain dual API routes for backward compatibility

Technical details:
- Use Zustand for state management
- Handle SSE streaming responses for AI chat
- Support document selection for Deep Read mode
- Implement batch processing with progress tracking

Known issues:
- Batch processing API integration pending
- Knowledge assets page navigation needs optimization

Status: Frontend functional, pending refinement

backend/src/modules/pkb/routes/health.ts

@@ -0,0 +1,45 @@
+/**
+ * PKB模块健康检查路由
+ */
+import { FastifyInstance, FastifyRequest, FastifyReply } from 'fastify';
+import { prisma } from '../../../config/database.js';
+
+export default async function healthRoutes(fastify: FastifyInstance) {
+  // PKB模块健康检查
+  fastify.get('/health', async (request: FastifyRequest, reply: FastifyReply) => {
+    try {
+      // 检查数据库连接
+      await prisma.$queryRaw`SELECT 1`;
+      
+      // 检查pkb_schema是否可访问
+      const kbCount = await prisma.knowledgeBase.count();
+      
+      return reply.send({
+        status: 'ok',
+        module: 'pkb',
+        version: 'v2',
+        timestamp: new Date().toISOString(),
+        database: {
+          connected: true,
+          schema: 'pkb_schema',
+          knowledgeBases: kbCount,
+        },
+        message: 'PKB模块运行正常',
+      });
+    } catch (error: any) {
+      return reply.status(503).send({
+        status: 'error',
+        module: 'pkb',
+        version: 'v2',
+        timestamp: new Date().toISOString(),
+        database: {
+          connected: false,
+          error: error.message,
+        },
+        message: 'PKB模块健康检查失败',
+      });
+    }
+  });
+}
+
+