fix: resolve all frontend lint errors and warnings

Replace all `any` types with proper types across 36 files:
- TanStack Router search params: `{} as Record<string, unknown>`
- API response pagination: proper typed interface
- DataTable column casts: remove unnecessary `as any`
- Function params and event handlers: use specific types
- Remove unused imports and variables in POS components

Frontend lint now passes with 0 errors and 0 warnings.

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

packages/admin/src/components/pos/pos-top-bar.tsx

@@ -1,6 +1,6 @@
 import { Link, useRouter } from '@tanstack/react-router'
 import { useAuthStore } from '@/stores/auth.store'
-import { usePOSStore } from '@/stores/pos.store'
+
 import { Button } from '@/components/ui/button'
 import { Badge } from '@/components/ui/badge'
 import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@/components/ui/select'