fix: Remove unused TypeScript imports and variables

- Remove unused ExternalLink import from ModuleStoreView
- Remove unused Tag import from StoreItemsView
- Prefix unused cmd variable with underscore in v-for loop

Fixes production build TypeScript errors.

frontend/src/views/admin/ModuleStoreView.vue

@@ -3,7 +3,7 @@ import { ref, computed, onMounted } from 'vue'
 import { useApi } from '@/composables/useApi'
 import { useAuthStore } from '@/stores/auth'
 import type { Module } from '@/types'
-import { ShoppingCart, Package, Search, Filter, X, Check, Download, AlertCircle, ExternalLink } from 'lucide-vue-next'
+import { ShoppingCart, Package, Search, Filter, X, Check, Download, AlertCircle } from 'lucide-vue-next'
 
 const api = useApi()
 const auth = useAuthStore()