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/package.json

@@ -0,0 +1,26 @@
+{
+  "name": "tasks",
+  "version": "0.1.0",
+  "private": true,
+  "scripts": {
+    "dev": "next dev",
+    "build": "next build",
+    "start": "next start",
+    "lint": "next lint"
+  },
+  "dependencies": {
+    "react": "^18",
+    "react-dom": "^18",
+    "next": "14.2.35"
+  },
+  "devDependencies": {
+    "typescript": "^5",
+    "@types/node": "^20",
+    "@types/react": "^18",
+    "@types/react-dom": "^18",
+    "postcss": "^8",
+    "tailwindcss": "^3.4.1",
+    "eslint": "^8",
+    "eslint-config-next": "14.2.35"
+  }
+}