feat(frontend): Implement Phase 2 - Complete Projects UI with CRUD operations

Implemented comprehensive Projects UI with full CRUD functionality following
modern React best practices and using shadcn/ui components.

Changes:
- Created ProjectForm component with react-hook-form + zod validation
  - Auto-uppercase project key input
  - Comprehensive field validation (name, key, description)
  - Support for both create and edit modes
  - Toast notifications for success/error states

- Enhanced Projects List Page (app/(dashboard)/projects/page.tsx)
  - Beautiful card-based grid layout with hover effects
  - Skeleton loading states for better UX
  - Empty state with call-to-action
  - Project metadata display (key badge, created date)
  - Integrated ProjectForm in Dialog for creation

- Enhanced Project Detail Page (app/(dashboard)/projects/[id]/page.tsx)
  - Comprehensive project information display
  - Edit functionality with dialog form
  - Delete functionality with confirmation AlertDialog
  - Epics preview section with stats
  - Quick actions sidebar (Kanban, Epics)
  - Statistics card (Total/Active/Completed epics)
  - Skeleton loading states
  - Error handling with retry capability

- Added toast notifications (Sonner)
  - Installed and configured sonner package
  - Added Toaster component to root layout
  - Success/error notifications for all CRUD operations

- Installed required dependencies
  - date-fns for date formatting
  - sonner for toast notifications
  - shadcn/ui alert-dialog component

Technical highlights:
- TypeScript with strict type checking
- React Query for data fetching and caching
- Optimistic updates with automatic rollback
- Responsive design (mobile-friendly)
- Accessibility-focused components
- Clean error handling throughout

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

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

components/ui/sonner.tsx

@@ -0,0 +1,40 @@
+"use client"
+
+import {
+  CircleCheckIcon,
+  InfoIcon,
+  Loader2Icon,
+  OctagonXIcon,
+  TriangleAlertIcon,
+} from "lucide-react"
+import { useTheme } from "next-themes"
+import { Toaster as Sonner, type ToasterProps } from "sonner"
+
+const Toaster = ({ ...props }: ToasterProps) => {
+  const { theme = "system" } = useTheme()
+
+  return (
+    <Sonner
+      theme={theme as ToasterProps["theme"]}
+      className="toaster group"
+      icons={{
+        success: <CircleCheckIcon className="size-4" />,
+        info: <InfoIcon className="size-4" />,
+        warning: <TriangleAlertIcon className="size-4" />,
+        error: <OctagonXIcon className="size-4" />,
+        loading: <Loader2Icon className="size-4 animate-spin" />,
+      }}
+      style={
+        {
+          "--normal-bg": "var(--popover)",
+          "--normal-text": "var(--popover-foreground)",
+          "--normal-border": "var(--border)",
+          "--border-radius": "var(--radius)",
+        } as React.CSSProperties
+      }
+      {...props}
+    />
+  )
+}
+
+export { Toaster }