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/enrollments/$enrollmentId.tsx

@@ -21,7 +21,7 @@ import { Dialog, DialogContent, DialogHeader, DialogTitle } from '@/components/u
 import { ArrowLeft, RefreshCw } from 'lucide-react'
 import { toast } from 'sonner'
 import { useAuthStore } from '@/stores/auth.store'
-import type { LessonSession, LessonPlan, LessonPlanTemplate } from '@/types/lesson'
+import type { Enrollment, LessonSession, LessonPlan, LessonPlanTemplate } from '@/types/lesson'
 
 export const Route = createFileRoute('/_authenticated/lessons/enrollments/$enrollmentId')({
   validateSearch: (search: Record<string, unknown>) => ({
@@ -81,7 +81,7 @@ function EnrollmentDetailPage() {
   const tab = search.tab
 
   function setTab(t: string) {
-    navigate({ to: '/lessons/enrollments/$enrollmentId', params: { enrollmentId }, search: { tab: t } as any })
+    navigate({ to: '/lessons/enrollments/$enrollmentId', params: { enrollmentId }, search: { tab: t } as Record<string, unknown> })
   }
 
   const { data: enrollment, isLoading } = useQuery(enrollmentDetailOptions(enrollmentId))
@@ -131,7 +131,7 @@ function EnrollmentDetailPage() {
   return (
     <div className="space-y-6">
       <div className="flex items-center gap-4">
-        <Button variant="ghost" size="sm" onClick={() => navigate({ to: '/lessons/enrollments', search: {} as any })}>
+        <Button variant="ghost" size="sm" onClick={() => navigate({ to: '/lessons/enrollments', search: {} as Record<string, unknown> })}>
           <ArrowLeft className="h-4 w-4 mr-1" />Back
         </Button>
         <div className="flex-1">
@@ -193,7 +193,17 @@ const BILLING_UNITS = [
 function DetailsTab({
   enrollment, slotLabel, lessonTypeName, instructorName,
   canEdit, onSave, saving, onStatusChange, statusChanging,
-}: any) {
+}: {
+  enrollment: Enrollment
+  slotLabel: string
+  lessonTypeName: string | undefined
+  instructorName: string | undefined
+  canEdit: boolean
+  onSave: (data: Record<string, unknown>) => void
+  saving: boolean
+  onStatusChange: (status: string) => void
+  statusChanging: boolean
+}) {
   const [rate, setRate] = useState(enrollment.rate ?? '')
   const [billingInterval, setBillingInterval] = useState(String(enrollment.billingInterval ?? 1))
   const [billingUnit, setBillingUnit] = useState(enrollment.billingUnit ?? 'month')
@@ -334,7 +344,7 @@ function SessionsTab({ enrollmentId, onGenerate, generating }: { enrollmentId: s
         total={data?.data?.length ?? 0}
         onPageChange={() => {}}
         onSort={() => {}}
-        onRowClick={(s) => navigate({ to: '/lessons/sessions/$sessionId', params: { sessionId: s.id }, search: {} as any })}
+        onRowClick={(s) => navigate({ to: '/lessons/sessions/$sessionId', params: { sessionId: s.id }, search: {} as Record<string, unknown> })}
       />
     </div>
   )
@@ -373,7 +383,7 @@ function LessonPlanTab({ enrollmentId, memberId, canEdit }: { enrollmentId: stri
       queryClient.invalidateQueries({ queryKey: lessonPlanKeys.all })
       toast.success('Plan created from template')
       setTemplatePickerOpen(false)
-      navigate({ to: '/lessons/plans/$planId', params: { planId: plan.id }, search: {} as any })
+      navigate({ to: '/lessons/plans/$planId', params: { planId: plan.id }, search: {} as Record<string, unknown> })
     },
     onError: (err) => toast.error(err.message),
   })
@@ -391,7 +401,7 @@ function LessonPlanTab({ enrollmentId, memberId, canEdit }: { enrollmentId: stri
                 {Math.round(activePlan.progress)}% complete
               </p>
             </div>
-            <Button variant="outline" size="sm" onClick={() => navigate({ to: '/lessons/plans/$planId', params: { planId: activePlan.id }, search: {} as any })}>
+            <Button variant="outline" size="sm" onClick={() => navigate({ to: '/lessons/plans/$planId', params: { planId: activePlan.id }, search: {} as Record<string, unknown> })}>
               View Plan
             </Button>
           </div>