feat: Implement caching for selectable products and enhance product filtering in admin panels

flutter/lib/features/admin/data/admin_repository.dart

@@ -21,9 +21,18 @@ final adminRepositoryProvider = Provider<AdminRepository>((ref) {
 class AdminRepository {
   final ApiClient _apiClient;
   final Ref _ref;
+  List<AdminProduct>? _selectableProductsCache;
+  DateTime? _selectableProductsCacheAt;
+
+  static const Duration _selectableProductsCacheTtl = Duration(seconds: 45);
 
   AdminRepository(this._apiClient, this._ref);
 
+  void _invalidateSelectableProductsCache() {
+    _selectableProductsCache = null;
+    _selectableProductsCacheAt = null;
+  }
+
   // ── Interna helpers ────────────────────────────────────────────────────────
 
   Future<String?> _token() => _ref.read(authStateProvider.future);
@@ -202,6 +211,50 @@ class AdminRepository {
   Future<List<PendingProduct>> listPrivateProducts() =>
       _getList(ProductApiPaths.privateList, PendingProduct.fromJson);
 
+  Future<List<AdminProduct>> listSelectableProductsForAdmin({
+    bool forceRefresh = false,
+  }) async {
+    final now = DateTime.now();
+    final cached = _selectableProductsCache;
+    final cacheAt = _selectableProductsCacheAt;
+    if (!forceRefresh && cached != null && cacheAt != null) {
+      if (now.difference(cacheAt) <= _selectableProductsCacheTtl) {
+        return List<AdminProduct>.from(cached);
+      }
+    }
+
+    final results = await Future.wait<dynamic>([
+      listProducts(),
+      listPrivateProducts(),
+    ]);
+    final globalProducts = results[0] as List<AdminProduct>;
+    final privateProducts = results[1] as List<PendingProduct>;
+
+    final merged = <int, AdminProduct>{
+      for (final product in globalProducts) product.id: product,
+    };
+
+    for (final product in privateProducts) {
+      merged[product.id] = AdminProduct(
+        id: product.id,
+        name: product.name,
+        canonicalName: product.canonicalName,
+        ownerId: product.ownerId,
+        categoryId: product.categoryId,
+        categoryPath: product.categoryPath,
+        status: 'private',
+      );
+    }
+
+    final list = merged.values.toList();
+    list.sort(
+      (a, b) => a.displayName.toLowerCase().compareTo(b.displayName.toLowerCase()),
+    );
+    _selectableProductsCache = List<AdminProduct>.from(list);
+    _selectableProductsCacheAt = now;
+    return list;
+  }
+
   Future<List<AdminProduct>> listDeletedProducts() =>
       _getList(ProductApiPaths.deleted, AdminProduct.fromJson);
 
@@ -209,36 +262,51 @@ class AdminRepository {
       _getList(ProductApiPaths.pending, PendingProduct.fromJson);
 
   Future<void> setProductStatus(int productId, String status) =>
-      _patchVoid(ProductApiPaths.setStatus(productId), {'status': status});
+      _patchVoid(ProductApiPaths.setStatus(productId), {'status': status}).then((_) {
+        _invalidateSelectableProductsCache();
+      });
 
   Future<AdminProduct> promotePrivateProduct(int productId) =>
       _post<AdminProduct>(
         ProductApiPaths.promotePrivate(productId),
         body: null,
         parse: (d) => AdminProduct.fromJson(Map<String, dynamic>.from(d as Map)),
-      );
+      ).then((value) {
+        _invalidateSelectableProductsCache();
+        return value;
+      });
 
   Future<void> setProductCategory(int productId, {required int? categoryId}) =>
-      _patchVoid(ProductApiPaths.update(productId), {'categoryId': categoryId});
+      _patchVoid(ProductApiPaths.update(productId), {'categoryId': categoryId}).then((_) {
+        _invalidateSelectableProductsCache();
+      });
 
   Future<void> removeProduct(int productId) =>
-      _deleteVoid(ProductApiPaths.remove(productId));
+      _deleteVoid(ProductApiPaths.remove(productId)).then((_) {
+        _invalidateSelectableProductsCache();
+      });
 
   Future<void> restoreProduct(int productId) =>
-      _postVoid(ProductApiPaths.restore(productId));
+      _postVoid(ProductApiPaths.restore(productId)).then((_) {
+        _invalidateSelectableProductsCache();
+      });
 
   // ── Product canonical name updates ────────────────────────────────────────
   Future<void> updateCanonicalName(int productId, String canonicalName) =>
       _patchVoid(
         ProductApiPaths.canonicalName(productId),
         {'canonicalName': canonicalName.trim()},
-      );
+      ).then((_) {
+        _invalidateSelectableProductsCache();
+      });
 
   Future<void> updateCanonicalNamePrivate(int productId, String canonicalName) =>
       _patchVoid(
         ProductApiPaths.canonicalNamePrivate(productId),
         {'canonicalName': canonicalName.trim()},
-      );
+      ).then((_) {
+        _invalidateSelectableProductsCache();
+      });
 
   // ── Product merging ────────────────────────────────────────────────────────
   Future<void> mergeProductsPrivate({
@@ -248,6 +316,8 @@ class AdminRepository {
       _postVoid(ProductApiPaths.mergePrivate, {
         'sourceProductId': sourceProductId,
         'targetProductId': targetProductId,
+      }).then((_) {
+        _invalidateSelectableProductsCache();
       });
 
   /// Skapar en ny aktiv produkt (kräver admin). Returnerar `{id, name, categoryId?}`.
@@ -258,7 +328,10 @@ class AdminRepository {
           'name': name.trim(),
           if (categoryId != null) 'categoryId': categoryId,
         },
-      );
+      ).then((value) {
+        _invalidateSelectableProductsCache();
+        return value;
+      });
 
   int _parseUpdatedCount(dynamic data) {
     if (data is! Map) {
@@ -274,7 +347,10 @@ class AdminRepository {
         ProductApiPaths.bulkUpdate,
         body: {'ids': ids, 'categoryId': categoryId},
         parse: _parseUpdatedCount,
-      );
+      ).then((value) {
+        _invalidateSelectableProductsCache();
+        return value;
+      });
 
   Future<void> mergeProducts({
     required int sourceProductId,
@@ -283,6 +359,8 @@ class AdminRepository {
       _postVoid(ProductApiPaths.merge, {
         'sourceProductId': sourceProductId,
         'targetProductId': targetProductId,
+      }).then((_) {
+        _invalidateSelectableProductsCache();
       });
 
   Future<Map<String, dynamic>> previewMerge({