feat(backoffice): redesign backoffice UI dengan shadcn/ui

Menyeluruh merancang ulang apps/backoffice memakai pola shadcn/ui sambil
mempertahankan seluruh palette warna existing (primary/neutral/success/
info/warning/danger) dan typography Bai Jamjuree.

UI library (libs/ui):
- Atoms existing (Button, Input, Label, Textarea, Card, Dialog, Drawer,
  Form, Select, Toggle) dirombak ke pola shadcn, API dipertahankan agar
  sibling apps (gacha, dimentorin, hackathon, qrcampaign) tidak break
- Select atom beralih dari native ke Radix Select + NativeSelect fallback
- 18 atom baru: Badge, Avatar, Separator, Skeleton, Tabs, Tooltip,
  DropdownMenu, Popover, AlertDialog, Checkbox, RadioGroup, Switch,
  ScrollArea, Sheet, Sidebar, Breadcrumb, Table, + use-mobile hook
- DataTable, Filter, BackofficeWrapper, Pagination, Modal (alias Dialog)
  direstyle dengan token baru
- CSS variable layer shadcn ditambahkan (--color-primary, --color-sidebar-*,
  dll) dipetakan ke palette existing; tw-animate-css di-import untuk
  transisi

Backoffice shell:
- Sidebar bersarang SidebarProvider + SidebarInset, built-in mobile Sheet,
  user DropdownMenu (Avatar + logout), ikon lucide-react

Pages redesign (19 list/dashboard/settings):
- accounts, cms-events, cms-testimonials, dashboard, dashboard-dimentorin
  (dengan recharts di Card), feedback-review-dimentorin, gacha-roll,
  hackathon-dashboard, hackathon-submissions, hackathon-teams,
  hackathon-users, permissions, prizes, roadmap-dimentorin, roles,
  session-dimentorin, settings-dimentorin (Tabs), transactions,
  users-dimentorin (Tabs mentor/mentee)
- Pola unified: BackofficeWrapper > Card (CardHeader toolbar + CardContent
  DataTable) + AlertDialog untuk delete confirm
- Form accounts_/$id diredesign; form pages lain tetap pakai
  ControlledInputField yang sekarang berbasis shadcn Input

Dependencies:
- +20 radix-ui primitives, lucide-react, cmdk, input-otp
- Select native patched di dimentorin (profile-sidebar, schedule step)
  untuk tetap kompatibel via NativeSelect alias

Verifikasi:
- nx build backoffice: sukses (2.33s, 4801 modules)
- nx build dimentorin/gacha/hackathon/qrcampaign: semua sukses (zero
  regresi dari rewrite libs/ui)

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

components.json

@@ -0,0 +1,21 @@
+{
+  "$schema": "https://ui.shadcn.com/schema.json",
+  "style": "new-york",
+  "rsc": false,
+  "tsx": true,
+  "tailwind": {
+    "config": "",
+    "css": "libs/ui/src/index.css",
+    "baseColor": "neutral",
+    "cssVariables": true,
+    "prefix": ""
+  },
+  "aliases": {
+    "components": "@imphnen-frontend-service/ui",
+    "utils": "@imphnen-frontend-service/utils",
+    "ui": "@imphnen-frontend-service/ui/atoms",
+    "lib": "@imphnen-frontend-service/utils",
+    "hooks": "@imphnen-frontend-service/utils"
+  },
+  "iconLibrary": "lucide"
+}