feat(frontend): Implement Epic detail page with Story management

Add comprehensive Epic detail page at /epics/[id] with full CRUD operations.

Changes:
- Created Epic detail page with breadcrumb navigation
- Display Epic details: name, description, status, priority, time estimates
- Show list of Stories belonging to the Epic with card view
- Add Edit Epic functionality (opens dialog with form)
- Add Create/Edit/Delete Story functionality under Epic
- Fix Epic type inconsistency (name vs title) across components
- Update Kanban page to map Epic.name to title for unified interface
- Update epic-form to use 'name' field and add createdBy support
- Update work-item-breadcrumb to use Epic.name instead of title

Technical improvements:
- Use Shadcn UI components for consistent design
- Implement optimistic updates with React Query
- Add loading and error states with skeletons
- Follow Next.js App Router patterns with async params
- Add delete confirmation dialogs for Epic and Stories

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

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

components/projects/work-item-breadcrumb.tsx

@@ -76,7 +76,7 @@ export function WorkItemBreadcrumb({
             className="flex items-center gap-1 text-muted-foreground hover:text-foreground transition-colors"
           >
             <Folder className="h-4 w-4 text-blue-500" />
-            <span className="max-w-[200px] truncate">{finalEpic.title}</span>
+            <span className="max-w-[200px] truncate">{finalEpic.name}</span>
           </Link>
         </>
       )}