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/api/pos.ts

@@ -119,7 +119,7 @@ export function currentDrawerOptions(locationId: string | null) {
 export function productSearchOptions(search: string) {
   return queryOptions({
     queryKey: posKeys.products(search),
-    queryFn: () => api.get<{ data: Product[]; pagination: any }>('/v1/products', { q: search, limit: 24, isActive: true }),
+    queryFn: () => api.get<{ data: Product[]; pagination: { page: number; limit: number; total: number; totalPages: number } }>('/v1/products', { q: search, limit: 24, isActive: true }),
     enabled: search.length >= 1,
   })
 }