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

frontend-v2/src/common/api/axios.ts

@@ -43,3 +43,4 @@ apiClient.interceptors.response.use(
 export default apiClient;
 
 
+