feat: add API optimizations, cache invalidation and comprehensive test suite

- Add abort controllers and request deduplication to composables
- Add entity type cache invalidation on create/update/delete flows
- Add 179 new tests (utilities, services, composables, components)
- Fix Vue runtime warnings in structure editors

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/composables/useProducts.ts

@@ -115,8 +115,16 @@ export function useProducts() {
       itemsPerPage = 30,
       orderBy = 'name',
       orderDir = 'asc',
+      force = false,
     } = options
 
+    if (!force && loaded.value && !search && page === 1) {
+      return {
+        success: true,
+        data: { items: products.value, total: total.value, page, itemsPerPage },
+      }
+    }
+
     if (loading.value) {
       return {
         success: true,