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/app/globals.css

@@ -0,0 +1,37 @@
+@tailwind base;
+@tailwind components;
+@tailwind utilities;
+
+:root {
+  --background: #ffffff;
+  --foreground: #171717;
+  --card: #f9fafb;
+  --card-border: #e5e7eb;
+  --muted: #6b7280;
+  --primary: #3b82f6;
+}
+
+.dark {
+  --background: #0a0a0a;
+  --foreground: #ededed;
+  --card: #1a1a2e;
+  --card-border: #2d2d44;
+  --muted: #9ca3af;
+  --primary: #60a5fa;
+}
+
+body {
+  background: var(--background);
+  color: var(--foreground);
+  font-family: system-ui, -apple-system, sans-serif;
+}
+
+@layer utilities {
+  .scrollbar-hide {
+    -ms-overflow-style: none;
+    scrollbar-width: none;
+  }
+  .scrollbar-hide::-webkit-scrollbar {
+    display: none;
+  }
+}