feat(frontend): Implement Phase 1 - ProjectManagement API Client & Hooks

Add complete API integration for ProjectManagement module:
- Epics, Stories, Tasks API clients
- React Query hooks for all entities
- Updated type definitions to match backend API
- API test page for connection verification

Changes:
- Update lib/api/config.ts: Add all ProjectManagement endpoints
- Update types/project.ts: Match backend API models (Epic, Story, Task)
- Create lib/api/pm.ts: API clients for Epics, Stories, Tasks
- Create lib/hooks/use-epics.ts: React Query hooks for Epic CRUD
- Create lib/hooks/use-stories.ts: React Query hooks for Story CRUD
- Create lib/hooks/use-tasks.ts: React Query hooks for Task CRUD
- Create app/(dashboard)/api-test/page.tsx: API connection test page

Features:
- Full CRUD operations for Epics, Stories, Tasks
- Status change and assignment operations
- Optimistic updates for better UX
- Error handling with toast notifications
- Query invalidation for cache consistency

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

lib/api/config.ts

@@ -1,4 +1,4 @@
-export const API_BASE_URL = process.env.NEXT_PUBLIC_API_URL || 'http://localhost:5000';
+export const API_BASE_URL = process.env.NEXT_PUBLIC_API_URL || 'http://localhost:5167';
 
 export const API_ENDPOINTS = {
   // Auth
@@ -17,7 +17,25 @@ export const API_ENDPOINTS = {
   ASSIGN_ROLE: (tenantId: string, userId: string) =>
     `/api/tenants/${tenantId}/users/${userId}/role`,
 
-  // Projects (to be implemented)
-  PROJECTS: '/api/projects',
-  PROJECT: (id: string) => `/api/projects/${id}`,
+  // Projects
+  PROJECTS: '/api/v1/projects',
+  PROJECT: (id: string) => `/api/v1/projects/${id}`,
+
+  // Epics
+  EPICS: '/api/v1/epics',
+  EPIC: (id: string) => `/api/v1/epics/${id}`,
+  EPIC_STATUS: (id: string) => `/api/v1/epics/${id}/status`,
+  EPIC_ASSIGN: (id: string) => `/api/v1/epics/${id}/assign`,
+
+  // Stories
+  STORIES: '/api/v1/stories',
+  STORY: (id: string) => `/api/v1/stories/${id}`,
+  STORY_STATUS: (id: string) => `/api/v1/stories/${id}/status`,
+  STORY_ASSIGN: (id: string) => `/api/v1/stories/${id}/assign`,
+
+  // Tasks
+  TASKS: '/api/v1/tasks',
+  TASK: (id: string) => `/api/v1/tasks/${id}`,
+  TASK_STATUS: (id: string) => `/api/v1/tasks/${id}/status`,
+  TASK_ASSIGN: (id: string) => `/api/v1/tasks/${id}/assign`,
 };