feat(frontend): Add SignalR Context for real-time event management

Create comprehensive SignalR Context infrastructure to support real-time updates across the application.

Changes:
- Created SignalRContext.tsx with React Context API for SignalR connection management
- Implemented useSignalREvent and useSignalREvents hooks for simplified event subscription
- Updated Kanban page to use new SignalR hooks (reduced from 150+ lines to ~50 lines)
- Updated root layout to use new SignalRProvider from SignalRContext
- Fixed login page Suspense boundary issue for Next.js 16 compatibility
- Fixed Kanban type issue: made description optional to match API response

Features:
- Auto-connect when user is authenticated
- Auto-reconnect with configurable delays (0s, 2s, 5s, 10s, 30s)
- Toast notifications for connection status changes
- Event subscription management with automatic cleanup
- Support for multiple hub connections (PROJECT, NOTIFICATION)
- TypeScript type safety with proper interfaces

Usage:
```tsx
// Subscribe to single event
useSignalREvent('TaskCreated', (task) => {
  console.log('Task created:', task);
});

// Subscribe to multiple events
useSignalREvents({
  'TaskCreated': (task) => handleTaskCreated(task),
  'TaskUpdated': (task) => handleTaskUpdated(task),
});
```

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

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

app/(auth)/login/page.tsx

@@ -9,6 +9,7 @@ import { Button } from '@/components/ui/button';
 import { Input } from '@/components/ui/input';
 import { Label } from '@/components/ui/label';
 import { useSearchParams } from 'next/navigation';
+import { Suspense } from 'react';
 
 const loginSchema = z.object({
   email: z.string().email('Invalid email address'),
@@ -18,7 +19,7 @@ const loginSchema = z.object({
 
 type LoginForm = z.infer<typeof loginSchema>;
 
-export default function LoginPage() {
+function LoginContent() {
   const searchParams = useSearchParams();
   const registered = searchParams.get('registered');
 
@@ -119,3 +120,18 @@ export default function LoginPage() {
     </div>
   );
 }
+
+export default function LoginPage() {
+  return (
+    <Suspense fallback={
+      <div className="flex min-h-screen items-center justify-center bg-gray-50">
+        <div className="text-center">
+          <div className="mx-auto h-12 w-12 animate-spin rounded-full border-b-2 border-blue-600"></div>
+          <p className="mt-4 text-gray-600">Loading...</p>
+        </div>
+      </div>
+    }>
+      <LoginContent />
+    </Suspense>
+  );
+}