Add Next.js frontend PWA

- Pages: login, register, tasks list, task detail
- Components: TaskCard, TaskForm, GroupSelector, StatusBadge, Header
- Tailwind CSS, dark/light mode, PWA manifest
- Running on :3001 via systemd

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/tasks/public/manifest.json

@@ -0,0 +1,22 @@
+{
+  "name": "Task Team",
+  "short_name": "Tasks",
+  "description": "Sprava ukolu pro tym",
+  "start_url": "/",
+  "display": "standalone",
+  "background_color": "#ffffff",
+  "theme_color": "#3b82f6",
+  "orientation": "portrait-primary",
+  "icons": [
+    {
+      "src": "/icon-192.png",
+      "sizes": "192x192",
+      "type": "image/png"
+    },
+    {
+      "src": "/icon-512.png",
+      "sizes": "512x512",
+      "type": "image/png"
+    }
+  ]
+}