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/roles/$roleId.tsx

@@ -100,7 +100,7 @@ function RoleDetailPage() {
   return (
     <div className="space-y-6 max-w-2xl">
       <div className="flex items-center gap-3">
-        <Button variant="ghost" size="sm" onClick={() => navigate({ to: '/roles', search: {} as any })}>
+        <Button variant="ghost" size="sm" onClick={() => navigate({ to: '/roles', search: {} as Record<string, unknown> })}>
           <ArrowLeft className="h-4 w-4" />
         </Button>
         <div>
@@ -177,7 +177,7 @@ function RoleDetailPage() {
         <Button onClick={handleSave} disabled={updateMutation.isPending}>
           {updateMutation.isPending ? 'Saving...' : 'Save Changes'}
         </Button>
-        <Button variant="secondary" onClick={() => navigate({ to: '/roles', search: {} as any })}>
+        <Button variant="secondary" onClick={() => navigate({ to: '/roles', search: {} as Record<string, unknown> })}>
           Cancel
         </Button>
       </div>

packages/admin/src/routes/_authenticated/roles/new.tsx

@@ -29,7 +29,7 @@ function NewRolePage() {
     onSuccess: () => {
       queryClient.invalidateQueries({ queryKey: rbacKeys.roles })
       toast.success('Role created')
-      navigate({ to: '/roles', search: {} as any })
+      navigate({ to: '/roles', search: {} as Record<string, unknown> })
     },
     onError: (err) => toast.error(err.message),
   })
@@ -153,7 +153,7 @@ function NewRolePage() {
         <Button onClick={handleSubmit} disabled={mutation.isPending}>
           {mutation.isPending ? 'Creating...' : 'Create Role'}
         </Button>
-        <Button variant="secondary" onClick={() => navigate({ to: '/roles', search: {} as any })}>
+        <Button variant="secondary" onClick={() => navigate({ to: '/roles', search: {} as Record<string, unknown> })}>
           Cancel
         </Button>
       </div>