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>

app/(dashboard)/epics/[id]/page.tsx

@@ -0,0 +1,533 @@
+'use client';
+
+import { use, useState } from 'react';
+import Link from 'next/link';
+import { useRouter } from 'next/navigation';
+import {
+  ArrowLeft,
+  Plus,
+  Edit,
+  Trash2,
+  Loader2,
+  Clock,
+  Calendar,
+  User,
+  ListTodo,
+} from 'lucide-react';
+import { Button } from '@/components/ui/button';
+import { Badge } from '@/components/ui/badge';
+import { Skeleton } from '@/components/ui/skeleton';
+import {
+  Card,
+  CardContent,
+  CardDescription,
+  CardHeader,
+  CardTitle,
+} from '@/components/ui/card';
+import {
+  Dialog,
+  DialogContent,
+  DialogDescription,
+  DialogHeader,
+  DialogTitle,
+} from '@/components/ui/dialog';
+import {
+  AlertDialog,
+  AlertDialogAction,
+  AlertDialogCancel,
+  AlertDialogContent,
+  AlertDialogDescription,
+  AlertDialogFooter,
+  AlertDialogHeader,
+  AlertDialogTitle,
+} from '@/components/ui/alert-dialog';
+import { useEpic, useDeleteEpic } from '@/lib/hooks/use-epics';
+import { useStories, useDeleteStory } from '@/lib/hooks/use-stories';
+import { useProject } from '@/lib/hooks/use-projects';
+import { EpicForm } from '@/components/epics/epic-form';
+import { StoryForm } from '@/components/projects/story-form';
+import { formatDistanceToNow } from 'date-fns';
+import { toast } from 'sonner';
+import type { Story, WorkItemStatus, WorkItemPriority } from '@/types/project';
+
+interface EpicDetailPageProps {
+  params: Promise<{ id: string }>;
+}
+
+export default function EpicDetailPage({ params }: EpicDetailPageProps) {
+  const { id: epicId } = use(params);
+  const router = useRouter();
+  const [isEditDialogOpen, setIsEditDialogOpen] = useState(false);
+  const [isCreateStoryDialogOpen, setIsCreateStoryDialogOpen] = useState(false);
+  const [editingStory, setEditingStory] = useState<Story | null>(null);
+  const [deletingStoryId, setDeletingStoryId] = useState<string | null>(null);
+  const [isDeleteEpicDialogOpen, setIsDeleteEpicDialogOpen] = useState(false);
+
+  const { data: epic, isLoading: epicLoading, error: epicError } = useEpic(epicId);
+  const { data: stories, isLoading: storiesLoading } = useStories(epicId);
+  const { data: project, isLoading: projectLoading } = useProject(epic?.projectId || '');
+  const deleteEpic = useDeleteEpic();
+  const deleteStory = useDeleteStory();
+
+  const handleDeleteEpic = async () => {
+    try {
+      await deleteEpic.mutateAsync(epicId);
+      toast.success('Epic deleted successfully');
+      router.push(`/projects/${epic?.projectId}/epics`);
+    } catch (error) {
+      const message = error instanceof Error ? error.message : 'Failed to delete epic';
+      toast.error(message);
+    }
+  };
+
+  const handleDeleteStory = async () => {
+    if (!deletingStoryId) return;
+
+    try {
+      await deleteStory.mutateAsync(deletingStoryId);
+      setDeletingStoryId(null);
+    } catch (error) {
+      const message = error instanceof Error ? error.message : 'Failed to delete story';
+      toast.error(message);
+    }
+  };
+
+  const getStatusColor = (status: WorkItemStatus) => {
+    switch (status) {
+      case 'Backlog':
+        return 'secondary';
+      case 'Todo':
+        return 'outline';
+      case 'InProgress':
+        return 'default';
+      case 'Done':
+        return 'success' as any;
+      default:
+        return 'secondary';
+    }
+  };
+
+  const getPriorityColor = (priority: WorkItemPriority) => {
+    switch (priority) {
+      case 'Low':
+        return 'bg-blue-100 text-blue-700 hover:bg-blue-100';
+      case 'Medium':
+        return 'bg-yellow-100 text-yellow-700 hover:bg-yellow-100';
+      case 'High':
+        return 'bg-orange-100 text-orange-700 hover:bg-orange-100';
+      case 'Critical':
+        return 'bg-red-100 text-red-700 hover:bg-red-100';
+      default:
+        return 'secondary';
+    }
+  };
+
+  if (epicLoading || projectLoading) {
+    return (
+      <div className="space-y-6">
+        <Skeleton className="h-10 w-96" />
+        <div className="flex items-start justify-between">
+          <div className="space-y-4 flex-1">
+            <Skeleton className="h-12 w-1/2" />
+            <Skeleton className="h-20 w-full" />
+          </div>
+          <Skeleton className="h-10 w-32" />
+        </div>
+        <Skeleton className="h-64 w-full" />
+      </div>
+    );
+  }
+
+  if (epicError || !epic) {
+    return (
+      <div className="flex items-center justify-center min-h-[400px]">
+        <Card className="w-full max-w-md">
+          <CardHeader>
+            <CardTitle className="text-destructive">Error Loading Epic</CardTitle>
+            <CardDescription>
+              {epicError instanceof Error ? epicError.message : 'Epic not found'}
+            </CardDescription>
+          </CardHeader>
+          <CardContent className="flex gap-2">
+            <Button onClick={() => router.back()}>Go Back</Button>
+            <Button onClick={() => window.location.reload()} variant="outline">
+              Retry
+            </Button>
+          </CardContent>
+        </Card>
+      </div>
+    );
+  }
+
+  return (
+    <div className="space-y-6">
+      {/* Breadcrumb */}
+      <div className="flex items-center gap-2 text-sm text-muted-foreground">
+        <Link href="/projects" className="hover:text-foreground">
+          Projects
+        </Link>
+        <span>/</span>
+        {project && (
+          <>
+            <Link href={`/projects/${project.id}`} className="hover:text-foreground">
+              {project.name}
+            </Link>
+            <span>/</span>
+          </>
+        )}
+        <Link href={`/projects/${epic.projectId}/epics`} className="hover:text-foreground">
+          Epics
+        </Link>
+        <span>/</span>
+        <span className="text-foreground">{epic.name}</span>
+      </div>
+
+      {/* Header */}
+      <div className="flex items-start justify-between gap-4">
+        <div className="space-y-2 flex-1">
+          <div className="flex items-center gap-3">
+            <Button variant="ghost" size="icon" onClick={() => router.back()}>
+              <ArrowLeft className="h-5 w-5" />
+            </Button>
+            <div className="flex-1">
+              <h1 className="text-3xl font-bold tracking-tight">{epic.name}</h1>
+              <div className="flex items-center gap-2 mt-2 flex-wrap">
+                <Badge variant={getStatusColor(epic.status)}>{epic.status}</Badge>
+                <Badge className={getPriorityColor(epic.priority)}>{epic.priority}</Badge>
+              </div>
+            </div>
+          </div>
+        </div>
+        <div className="flex gap-2">
+          <Button variant="outline" onClick={() => setIsEditDialogOpen(true)}>
+            <Edit className="mr-2 h-4 w-4" />
+            Edit Epic
+          </Button>
+          <Button
+            variant="destructive"
+            onClick={() => setIsDeleteEpicDialogOpen(true)}
+          >
+            <Trash2 className="mr-2 h-4 w-4" />
+            Delete
+          </Button>
+        </div>
+      </div>
+
+      {/* Epic Details Card */}
+      <Card>
+        <CardHeader>
+          <CardTitle>Epic Details</CardTitle>
+        </CardHeader>
+        <CardContent className="space-y-4">
+          {epic.description ? (
+            <div>
+              <h3 className="text-sm font-medium text-muted-foreground mb-2">
+                Description
+              </h3>
+              <p className="text-sm whitespace-pre-wrap">{epic.description}</p>
+            </div>
+          ) : (
+            <p className="text-sm text-muted-foreground italic">No description</p>
+          )}
+
+          <div className="grid grid-cols-1 md:grid-cols-2 gap-4 pt-4 border-t">
+            {epic.estimatedHours !== undefined && (
+              <div className="flex items-start gap-2">
+                <Clock className="h-4 w-4 text-muted-foreground mt-0.5" />
+                <div>
+                  <p className="text-sm font-medium">Time Estimate</p>
+                  <p className="text-sm text-muted-foreground">
+                    Estimated: {epic.estimatedHours}h
+                    {epic.actualHours !== undefined && (
+                      <> / Actual: {epic.actualHours}h</>
+                    )}
+                  </p>
+                </div>
+              </div>
+            )}
+
+            {epic.assigneeId && (
+              <div className="flex items-start gap-2">
+                <User className="h-4 w-4 text-muted-foreground mt-0.5" />
+                <div>
+                  <p className="text-sm font-medium">Assignee</p>
+                  <p className="text-sm text-muted-foreground">{epic.assigneeId}</p>
+                </div>
+              </div>
+            )}
+
+            <div className="flex items-start gap-2">
+              <Calendar className="h-4 w-4 text-muted-foreground mt-0.5" />
+              <div>
+                <p className="text-sm font-medium">Created</p>
+                <p className="text-sm text-muted-foreground">
+                  {formatDistanceToNow(new Date(epic.createdAt), { addSuffix: true })}
+                  {epic.createdBy && <> by {epic.createdBy}</>}
+                </p>
+              </div>
+            </div>
+
+            <div className="flex items-start gap-2">
+              <Calendar className="h-4 w-4 text-muted-foreground mt-0.5" />
+              <div>
+                <p className="text-sm font-medium">Last Updated</p>
+                <p className="text-sm text-muted-foreground">
+                  {formatDistanceToNow(new Date(epic.updatedAt), { addSuffix: true })}
+                </p>
+              </div>
+            </div>
+          </div>
+        </CardContent>
+      </Card>
+
+      {/* Stories Section */}
+      <div className="space-y-4">
+        <div className="flex items-center justify-between">
+          <h2 className="text-2xl font-bold tracking-tight">Stories</h2>
+          <Button onClick={() => setIsCreateStoryDialogOpen(true)}>
+            <Plus className="mr-2 h-4 w-4" />
+            New Story
+          </Button>
+        </div>
+
+        {storiesLoading ? (
+          <div className="grid gap-4 md:grid-cols-2">
+            {Array.from({ length: 4 }).map((_, i) => (
+              <Card key={i}>
+                <CardHeader>
+                  <Skeleton className="h-6 w-3/4" />
+                  <Skeleton className="h-4 w-1/2 mt-2" />
+                </CardHeader>
+                <CardContent>
+                  <Skeleton className="h-16 w-full" />
+                </CardContent>
+              </Card>
+            ))}
+          </div>
+        ) : stories && stories.length > 0 ? (
+          <div className="grid gap-4 md:grid-cols-2">
+            {stories.map((story) => (
+              <Card
+                key={story.id}
+                className="group transition-all hover:shadow-lg hover:border-primary"
+              >
+                <CardHeader>
+                  <div className="flex items-start justify-between gap-2">
+                    <div className="space-y-2 flex-1">
+                      <Link
+                        href={`/stories/${story.id}`}
+                        className="block hover:underline"
+                      >
+                        <CardTitle className="line-clamp-2 text-lg">
+                          {story.title}
+                        </CardTitle>
+                      </Link>
+                      <div className="flex items-center gap-2 flex-wrap">
+                        <Badge variant={getStatusColor(story.status)}>
+                          {story.status}
+                        </Badge>
+                        <Badge className={getPriorityColor(story.priority)}>
+                          {story.priority}
+                        </Badge>
+                      </div>
+                    </div>
+                    <div className="flex gap-1 opacity-0 group-hover:opacity-100 transition-opacity">
+                      <Button
+                        variant="ghost"
+                        size="icon"
+                        className="h-8 w-8"
+                        onClick={(e) => {
+                          e.preventDefault();
+                          setEditingStory(story);
+                        }}
+                      >
+                        <Edit className="h-4 w-4" />
+                      </Button>
+                      <Button
+                        variant="ghost"
+                        size="icon"
+                        className="h-8 w-8 text-destructive hover:text-destructive"
+                        onClick={(e) => {
+                          e.preventDefault();
+                          setDeletingStoryId(story.id);
+                        }}
+                      >
+                        <Trash2 className="h-4 w-4" />
+                      </Button>
+                    </div>
+                  </div>
+                </CardHeader>
+                <CardContent className="space-y-4">
+                  {story.description ? (
+                    <p className="text-sm text-muted-foreground line-clamp-3">
+                      {story.description}
+                    </p>
+                  ) : (
+                    <p className="text-sm text-muted-foreground italic">
+                      No description
+                    </p>
+                  )}
+                  <div className="space-y-2 text-xs text-muted-foreground">
+                    {story.estimatedHours && (
+                      <div className="flex items-center gap-1">
+                        <Clock className="h-3 w-3" />
+                        <span>Estimated: {story.estimatedHours}h</span>
+                        {story.actualHours && (
+                          <span className="ml-2">
+                            / Actual: {story.actualHours}h
+                          </span>
+                        )}
+                      </div>
+                    )}
+                    <div className="flex items-center gap-1">
+                      <Calendar className="h-3 w-3" />
+                      <span>
+                        Created{' '}
+                        {formatDistanceToNow(new Date(story.createdAt), {
+                          addSuffix: true,
+                        })}
+                      </span>
+                    </div>
+                  </div>
+                </CardContent>
+              </Card>
+            ))}
+          </div>
+        ) : (
+          <Card className="flex flex-col items-center justify-center py-16">
+            <ListTodo className="h-12 w-12 text-muted-foreground mb-4" />
+            <CardTitle className="mb-2">No stories yet</CardTitle>
+            <CardDescription className="mb-4 text-center max-w-md">
+              Get started by creating your first story to break down this epic
+            </CardDescription>
+            <Button onClick={() => setIsCreateStoryDialogOpen(true)}>
+              <Plus className="mr-2 h-4 w-4" />
+              Create Story
+            </Button>
+          </Card>
+        )}
+      </div>
+
+      {/* Edit Epic Dialog */}
+      <Dialog open={isEditDialogOpen} onOpenChange={setIsEditDialogOpen}>
+        <DialogContent className="max-w-2xl max-h-[90vh] overflow-y-auto">
+          <DialogHeader>
+            <DialogTitle>Edit Epic</DialogTitle>
+            <DialogDescription>Update the epic details</DialogDescription>
+          </DialogHeader>
+          <EpicForm
+            projectId={epic.projectId}
+            epic={epic}
+            onSuccess={() => setIsEditDialogOpen(false)}
+            onCancel={() => setIsEditDialogOpen(false)}
+          />
+        </DialogContent>
+      </Dialog>
+
+      {/* Create Story Dialog */}
+      <Dialog
+        open={isCreateStoryDialogOpen}
+        onOpenChange={setIsCreateStoryDialogOpen}
+      >
+        <DialogContent className="max-w-2xl max-h-[90vh] overflow-y-auto">
+          <DialogHeader>
+            <DialogTitle>Create New Story</DialogTitle>
+            <DialogDescription>
+              Add a new story under {epic.name}
+            </DialogDescription>
+          </DialogHeader>
+          <StoryForm
+            epicId={epicId}
+            projectId={epic.projectId}
+            onSuccess={() => setIsCreateStoryDialogOpen(false)}
+            onCancel={() => setIsCreateStoryDialogOpen(false)}
+          />
+        </DialogContent>
+      </Dialog>
+
+      {/* Edit Story Dialog */}
+      <Dialog open={!!editingStory} onOpenChange={() => setEditingStory(null)}>
+        <DialogContent className="max-w-2xl max-h-[90vh] overflow-y-auto">
+          <DialogHeader>
+            <DialogTitle>Edit Story</DialogTitle>
+            <DialogDescription>Update the story details</DialogDescription>
+          </DialogHeader>
+          {editingStory && (
+            <StoryForm
+              story={editingStory}
+              projectId={epic.projectId}
+              onSuccess={() => setEditingStory(null)}
+              onCancel={() => setEditingStory(null)}
+            />
+          )}
+        </DialogContent>
+      </Dialog>
+
+      {/* Delete Epic Confirmation Dialog */}
+      <AlertDialog
+        open={isDeleteEpicDialogOpen}
+        onOpenChange={setIsDeleteEpicDialogOpen}
+      >
+        <AlertDialogContent>
+          <AlertDialogHeader>
+            <AlertDialogTitle>Are you sure?</AlertDialogTitle>
+            <AlertDialogDescription>
+              This action cannot be undone. This will permanently delete the epic
+              and all its associated stories and tasks.
+            </AlertDialogDescription>
+          </AlertDialogHeader>
+          <AlertDialogFooter>
+            <AlertDialogCancel>Cancel</AlertDialogCancel>
+            <AlertDialogAction
+              onClick={handleDeleteEpic}
+              className="bg-destructive text-destructive-foreground hover:bg-destructive/90"
+              disabled={deleteEpic.isPending}
+            >
+              {deleteEpic.isPending ? (
+                <>
+                  <Loader2 className="mr-2 h-4 w-4 animate-spin" />
+                  Deleting...
+                </>
+              ) : (
+                'Delete Epic'
+              )}
+            </AlertDialogAction>
+          </AlertDialogFooter>
+        </AlertDialogContent>
+      </AlertDialog>
+
+      {/* Delete Story Confirmation Dialog */}
+      <AlertDialog
+        open={!!deletingStoryId}
+        onOpenChange={() => setDeletingStoryId(null)}
+      >
+        <AlertDialogContent>
+          <AlertDialogHeader>
+            <AlertDialogTitle>Are you sure?</AlertDialogTitle>
+            <AlertDialogDescription>
+              This action cannot be undone. This will permanently delete the story
+              and all its associated tasks.
+            </AlertDialogDescription>
+          </AlertDialogHeader>
+          <AlertDialogFooter>
+            <AlertDialogCancel>Cancel</AlertDialogCancel>
+            <AlertDialogAction
+              onClick={handleDeleteStory}
+              className="bg-destructive text-destructive-foreground hover:bg-destructive/90"
+              disabled={deleteStory.isPending}
+            >
+              {deleteStory.isPending ? (
+                <>
+                  <Loader2 className="mr-2 h-4 w-4 animate-spin" />
+                  Deleting...
+                </>
+              ) : (
+                'Delete Story'
+              )}
+            </AlertDialogAction>
+          </AlertDialogFooter>
+        </AlertDialogContent>
+      </AlertDialog>
+    </div>
+  );
+}

app/(dashboard)/projects/[id]/kanban/page.tsx

@@ -125,6 +125,7 @@ export default function KanbanPage() {
     const items: KanbanWorkItem[] = [
       ...(epics || []).map((e) => ({
         ...e,
+        title: e.name, // Epic uses 'name', map to 'title' for unified interface
         type: 'Epic' as const,
       })),
       ...(stories || []).map((s) => ({

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>
           )}

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>
         </>
       )}