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

frontend-v2/src/modules/pkb/api/knowledgeBaseApi.ts

@@ -0,0 +1,217 @@
+/**
+ * PKB个人知识库 API（v2版本）
+ * 更新API路径为 /api/v2/pkb/knowledge
+ */
+
+import axios from 'axios';
+
+const API_BASE_URL = import.meta.env.VITE_API_BASE_URL || 'http://localhost:3000';
+
+const api = axios.create({
+  baseURL: `${API_BASE_URL}/api/v2/pkb/knowledge`,
+  timeout: 30000,
+  headers: {
+    'Content-Type': 'application/json',
+  },
+});
+
+/**
+ * 知识库类型定义
+ */
+export interface KnowledgeBase {
+  id: string;
+  userId: string;
+  name: string;
+  description?: string;
+  difyDatasetId: string;
+  fileCount: number;
+  totalSizeBytes: number;
+  createdAt: string;
+  updatedAt: string;
+  _count?: {
+    documents: number;
+  };
+}
+
+export interface Document {
+  id: string;
+  kbId: string;
+  userId: string;
+  filename: string;
+  fileType: string;
+  fileSizeBytes: number;
+  fileUrl: string;
+  difyDocumentId: string;
+  status: 'uploading' | 'parsing' | 'indexing' | 'completed' | 'error';
+  progress: number;
+  errorMessage?: string;
+  segmentsCount?: number;
+  tokensCount?: number;
+  uploadedAt: string;
+  processedAt?: string;
+}
+
+export interface CreateKnowledgeBaseRequest {
+  name: string;
+  description?: string;
+}
+
+export interface UpdateKnowledgeBaseRequest {
+  name?: string;
+  description?: string;
+}
+
+export interface KnowledgeBaseStats {
+  totalDocuments: number;
+  completedDocuments: number;
+  processingDocuments: number;
+  errorDocuments: number;
+  totalSizeBytes: number;
+  totalTokens: number;
+}
+
+/**
+ * 知识库管理API
+ */
+export const knowledgeBaseApi = {
+  /**
+   * 获取知识库列表
+   */
+  async getList(): Promise<KnowledgeBase[]> {
+    const response = await api.get('/knowledge-bases');
+    return response.data.data;
+  },
+
+  /**
+   * 获取知识库详情
+   */
+  async getById(id: string): Promise<KnowledgeBase> {
+    const response = await api.get(`/knowledge-bases/${id}`);
+    return response.data.data;
+  },
+
+  /**
+   * 创建知识库
+   */
+  async create(data: CreateKnowledgeBaseRequest): Promise<KnowledgeBase> {
+    const response = await api.post('/knowledge-bases', data);
+    return response.data.data;
+  },
+
+  /**
+   * 更新知识库
+   */
+  async update(id: string, data: UpdateKnowledgeBaseRequest): Promise<KnowledgeBase> {
+    const response = await api.put(`/knowledge-bases/${id}`, data);
+    return response.data.data;
+  },
+
+  /**
+   * 删除知识库
+   */
+  async delete(id: string): Promise<void> {
+    await api.delete(`/knowledge-bases/${id}`);
+  },
+
+  /**
+   * 获取知识库统计信息
+   */
+  async getStats(id: string): Promise<KnowledgeBaseStats> {
+    const response = await api.get(`/knowledge-bases/${id}/stats`);
+    return response.data.data;
+  },
+
+  /**
+   * 检索知识库（RAG）
+   */
+  async search(id: string, query: string, topK: number = 3): Promise<any> {
+    const response = await api.get(`/knowledge-bases/${id}/search`, {
+      params: { query, top_k: topK },
+    });
+    return response.data.data;
+  },
+};
+
+/**
+ * 文档管理API
+ */
+export const documentApi = {
+  /**
+   * 获取文档列表
+   */
+  async getList(kbId: string): Promise<Document[]> {
+    const response = await api.get(`/knowledge-bases/${kbId}/documents`);
+    return response.data.data;
+  },
+
+  /**
+   * 获取文档详情
+   */
+  async getById(id: string): Promise<Document> {
+    const response = await api.get(`/documents/${id}`);
+    return response.data.data;
+  },
+
+  /**
+   * 上传文档
+   */
+  async upload(kbId: string, file: File, onProgress?: (progress: number) => void): Promise<Document> {
+    const formData = new FormData();
+    formData.append('file', file);
+
+    const response = await api.post(`/knowledge-bases/${kbId}/documents`, formData, {
+      headers: {
+        'Content-Type': 'multipart/form-data',
+      },
+      onUploadProgress: (progressEvent) => {
+        if (progressEvent.total && onProgress) {
+          const percentCompleted = Math.round((progressEvent.loaded * 100) / progressEvent.total);
+          onProgress(percentCompleted);
+        }
+      },
+    });
+    return response.data.data;
+  },
+
+  /**
+   * 删除文档
+   */
+  async delete(id: string): Promise<void> {
+    await api.delete(`/documents/${id}`);
+  },
+
+  /**
+   * 重新处理文档
+   */
+  async reprocess(id: string): Promise<void> {
+    await api.post(`/documents/${id}/reprocess`);
+  },
+
+  /**
+   * 获取文档全文（用于逐篇精读模式）
+   */
+  async getFullText(id: string): Promise<any> {
+    const response = await api.get(`/documents/${id}/full-text`);
+    return response.data;
+  },
+};
+
+/**
+ * 文档选择API（用于全文阅读模式）
+ */
+export const documentSelectionApi = {
+  /**
+   * 获取知识库的文档选择结果
+   */
+  async getSelection(kbId: string, maxFiles?: number, maxTokens?: number): Promise<any> {
+    const params = new URLSearchParams();
+    if (maxFiles) params.append('max_files', maxFiles.toString());
+    if (maxTokens) params.append('max_tokens', maxTokens.toString());
+    
+    const url = `/knowledge-bases/${kbId}/document-selection${params.toString() ? '?' + params.toString() : ''}`;
+    const response = await api.get(url);
+    return response.data.data;
+  },
+};
+
+