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/epic-form.tsx

@@ -26,13 +26,14 @@ import { useCreateEpic, useUpdateEpic } from '@/lib/hooks/use-epics';
 import type { Epic, WorkItemPriority } from '@/types/project';
 import { toast } from 'sonner';
 import { Loader2 } from 'lucide-react';
+import { useAuthStore } from '@/stores/authStore';
 
 const epicSchema = z.object({
   projectId: z.string().min(1, 'Project is required'),
-  title: z
+  name: z
     .string()
-    .min(1, 'Title is required')
-    .max(200, 'Title must be less than 200 characters'),
+    .min(1, 'Name is required')
+    .max(200, 'Name must be less than 200 characters'),
   description: z
     .string()
     .max(2000, 'Description must be less than 2000 characters')
@@ -58,12 +59,13 @@ export function EpicForm({ epic, projectId, onSuccess, onCancel }: EpicFormProps
   const isEditing = !!epic;
   const createEpic = useCreateEpic();
   const updateEpic = useUpdateEpic();
+  const user = useAuthStore((state) => state.user);
 
   const form = useForm<EpicFormValues>({
     resolver: zodResolver(epicSchema),
     defaultValues: {
       projectId: epic?.projectId || projectId || '',
-      title: epic?.title || '',
+      name: epic?.name || '',
       description: epic?.description || '',
       priority: epic?.priority || 'Medium',
       estimatedHours: epic?.estimatedHours || ('' as any),
@@ -72,11 +74,16 @@ export function EpicForm({ epic, projectId, onSuccess, onCancel }: EpicFormProps
 
   async function onSubmit(data: EpicFormValues) {
     try {
+      if (!user?.id) {
+        toast.error('User not authenticated');
+        return;
+      }
+
       if (isEditing && epic) {
         await updateEpic.mutateAsync({
           id: epic.id,
           data: {
-            title: data.title,
+            name: data.name,
             description: data.description,
             priority: data.priority,
             estimatedHours:
@@ -87,11 +94,12 @@ export function EpicForm({ epic, projectId, onSuccess, onCancel }: EpicFormProps
       } else {
         await createEpic.mutateAsync({
           projectId: data.projectId,
-          title: data.title,
+          name: data.name,
           description: data.description,
           priority: data.priority,
           estimatedHours:
             typeof data.estimatedHours === 'number' ? data.estimatedHours : undefined,
+          createdBy: user.id,
         });
         toast.success('Epic created successfully');
       }
@@ -109,14 +117,14 @@ export function EpicForm({ epic, projectId, onSuccess, onCancel }: EpicFormProps
       <form onSubmit={form.handleSubmit(onSubmit)} className="space-y-6">
         <FormField
           control={form.control}
-          name="title"
+          name="name"
           render={({ field }) => (
             <FormItem>
-              <FormLabel>Epic Title *</FormLabel>
+              <FormLabel>Epic Name *</FormLabel>
               <FormControl>
                 <Input placeholder="e.g., User Authentication System" {...field} />
               </FormControl>
-              <FormDescription>A clear, concise title for this epic</FormDescription>
+              <FormDescription>A clear, concise name for this epic</FormDescription>
               <FormMessage />
             </FormItem>
           )}