fix(pkb): fix create KB and upload issues - remove simulated upload, fix department mapping, add upload modal

Fixed issues:
- Remove simulateUpload function from DashboardPage Step 3
- Map department to description field when creating KB
- Add upload modal in WorkspacePage knowledge assets tab
- Fix DocumentUpload import path (../../stores to ../stores)

Known issue: Dify API validation error during document upload (file uploaded but DB record failed, needs investigation)

Testing: KB creation works, upload dialog opens correctly

backend/src/modules/pkb/controllers/knowledgeBaseController.ts

@@ -1,8 +1,16 @@
 import type { FastifyRequest, FastifyReply } from 'fastify';
 import * as knowledgeBaseService from '../services/knowledgeBaseService.js';
 
-// Mock用户ID（实际应从JWT token中获取）
-const MOCK_USER_ID = 'user-mock-001';
+/**
+ * 获取用户ID（从JWT Token中获取）
+ */
+function getUserId(request: FastifyRequest): string {
+  const userId = (request as any).user?.userId;
+  if (!userId) {
+    throw new Error('User not authenticated');
+  }
+  return userId;
+}
 
 /**
  * 创建知识库
@@ -26,8 +34,9 @@ export async function createKnowledgeBase(
       });
     }
 
+    const userId = getUserId(request);
     const knowledgeBase = await knowledgeBaseService.createKnowledgeBase(
-      MOCK_USER_ID,
+      userId,
       name,
       description
     );
@@ -49,12 +58,13 @@ export async function createKnowledgeBase(
  * 获取知识库列表
  */
 export async function getKnowledgeBases(
-  _request: FastifyRequest,
+  request: FastifyRequest,
   reply: FastifyReply
 ) {
   try {
+    const userId = getUserId(request);
     const knowledgeBases = await knowledgeBaseService.getKnowledgeBases(
-      MOCK_USER_ID
+      userId
     );
 
     return reply.send({
@@ -84,8 +94,9 @@ export async function getKnowledgeBaseById(
   try {
     const { id } = request.params;
 
+    const userId = getUserId(request);
     const knowledgeBase = await knowledgeBaseService.getKnowledgeBaseById(
-      MOCK_USER_ID,
+      userId,
       id
     );
 
@@ -129,8 +140,9 @@ export async function updateKnowledgeBase(
     const { id } = request.params;
     const updateData = request.body;
 
+    const userId = getUserId(request);
     const knowledgeBase = await knowledgeBaseService.updateKnowledgeBase(
-      MOCK_USER_ID,
+      userId,
       id,
       updateData
     );
@@ -170,7 +182,8 @@ export async function deleteKnowledgeBase(
   try {
     const { id } = request.params;
 
-    await knowledgeBaseService.deleteKnowledgeBase(MOCK_USER_ID, id);
+    const userId = getUserId(request);
+    await knowledgeBaseService.deleteKnowledgeBase(userId, id);
 
     return reply.send({
       success: true,
@@ -221,8 +234,9 @@ export async function searchKnowledgeBase(
 
     const topK = top_k ? parseInt(top_k, 10) : 15;  // Phase 1优化：默认从3增加到15
 
+    const userId = getUserId(request);
     const results = await knowledgeBaseService.searchKnowledgeBase(
-      MOCK_USER_ID,
+      userId,
       id,
       query,
       topK
@@ -263,8 +277,9 @@ export async function getKnowledgeBaseStats(
   try {
     const { id } = request.params;
 
+    const userId = getUserId(request);
     const stats = await knowledgeBaseService.getKnowledgeBaseStats(
-      MOCK_USER_ID,
+      userId,
       id
     );
 
@@ -311,8 +326,9 @@ export async function getDocumentSelection(
     const maxFiles = max_files ? parseInt(max_files, 10) : undefined;
     const maxTokens = max_tokens ? parseInt(max_tokens, 10) : undefined;
 
+    const userId = getUserId(request);
     const selection = await knowledgeBaseService.getDocumentSelection(
-      MOCK_USER_ID,
+      userId,
       id,
       maxFiles,
       maxTokens