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/routes/_authenticated/lessons/schedule/index.tsx

@@ -49,7 +49,7 @@ function ScheduleHubPage() {
   const canAdmin = hasPermission('lessons.admin')
 
   function setTab(t: string) {
-    navigate({ to: '/lessons/schedule', search: { ...search, tab: t, page: 1 } as any })
+    navigate({ to: '/lessons/schedule', search: { ...search, tab: t, page: 1 } as Record<string, unknown> })
   }
 
   return (
@@ -90,7 +90,7 @@ const instructorColumns: Column<Instructor>[] = [
   },
 ]
 
-function InstructorsTab({ canAdmin, search: _search }: { canAdmin: boolean; search: any }) {
+function InstructorsTab({ canAdmin, search: _search }: { canAdmin: boolean; search: Record<string, unknown> }) {
   const navigate = useNavigate()
   const queryClient = useQueryClient()
   const { params, setPage, setSearch, setSort } = usePagination()
@@ -152,7 +152,7 @@ function InstructorsTab({ canAdmin, search: _search }: { canAdmin: boolean; sear
         order={params.order}
         onPageChange={setPage}
         onSort={setSort}
-        onRowClick={(i) => navigate({ to: '/lessons/schedule/instructors/$instructorId', params: { instructorId: i.id }, search: {} as any })}
+        onRowClick={(i) => navigate({ to: '/lessons/schedule/instructors/$instructorId', params: { instructorId: i.id }, search: {} as Record<string, unknown> })}
       />
     </div>
   )
@@ -169,7 +169,7 @@ const lessonTypeColumns: Column<LessonType>[] = [
   { key: 'is_active', header: 'Status', render: (lt) => <Badge variant={lt.isActive ? 'default' : 'secondary'}>{lt.isActive ? 'Active' : 'Inactive'}</Badge> },
 ]
 
-function LessonTypesTab({ canAdmin, search: _search }: { canAdmin: boolean; search: any }) {
+function LessonTypesTab({ canAdmin, search: _search }: { canAdmin: boolean; search: Record<string, unknown> }) {
   const queryClient = useQueryClient()
   const { params, setPage, setSearch, setSort } = usePagination()
   const [searchInput, setSearchInput] = useState(params.q ?? '')
@@ -215,8 +215,8 @@ function LessonTypesTab({ canAdmin, search: _search }: { canAdmin: boolean; sear
   const columnsWithActions: Column<LessonType>[] = [
     ...lessonTypeColumns,
     ...(canAdmin ? [{
-      key: 'actions' as any,
-      header: '' as any,
+      key: 'actions',
+      header: '',
       render: (lt: LessonType) => (
         <div className="flex gap-1 justify-end">
           <Button variant="ghost" size="sm" onClick={(e) => { e.stopPropagation(); setEditTarget(lt) }}>Edit</Button>
@@ -298,7 +298,7 @@ const gradingScaleColumns: Column<GradingScale>[] = [
   { key: 'is_active', header: 'Status', render: (gs) => <Badge variant={gs.isActive ? 'default' : 'secondary'}>{gs.isActive ? 'Active' : 'Inactive'}</Badge> },
 ]
 
-function GradingScalesTab({ canAdmin, search: _search }: { canAdmin: boolean; search: any }) {
+function GradingScalesTab({ canAdmin, search: _search }: { canAdmin: boolean; search: Record<string, unknown> }) {
   const queryClient = useQueryClient()
   const { params, setPage, setSort } = usePagination()
   const [createOpen, setCreateOpen] = useState(false)
@@ -327,8 +327,8 @@ function GradingScalesTab({ canAdmin, search: _search }: { canAdmin: boolean; se
   const columnsWithActions: Column<GradingScale>[] = [
     ...gradingScaleColumns,
     ...(canAdmin ? [{
-      key: 'actions' as any,
-      header: '' as any,
+      key: 'actions',
+      header: '',
       render: (gs: GradingScale) => (
         <Button variant="ghost" size="sm" onClick={(e) => { e.stopPropagation(); deleteMutation.mutate(gs.id) }}>
           <Trash2 className="h-4 w-4 text-destructive" />