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/hooks/use-pagination.ts

@@ -23,12 +23,12 @@ export function usePagination() {
 
   function setParams(updates: Partial<PaginationSearch>) {
     navigate({
-      search: ((prev: PaginationSearch) => ({
+      search: ((prev: Record<string, unknown>) => ({
         ...prev,
         ...updates,
         // Reset to page 1 when search or sort changes
-        page: updates.q !== undefined || updates.sort !== undefined ? 1 : (updates.page ?? prev.page),
-      })) as any,
+        page: updates.q !== undefined || updates.sort !== undefined ? 1 : (updates.page ?? (prev as PaginationSearch).page),
+      })) as (prev: Record<string, unknown>) => Record<string, unknown>,
       replace: true,
     })
   }