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

flutter/lib/features/admin/domain/admin_product.dart

@@ -3,6 +3,7 @@ class AdminProduct {
   final String name;
   final String? canonicalName;
   final String? normalizedName;
+  final int? ownerId;
   final int? categoryId;
   final String? categoryPath;
   final bool? isActive;
@@ -14,6 +15,7 @@ class AdminProduct {
     required this.name,
     this.canonicalName,
     this.normalizedName,
+    this.ownerId,
     this.categoryId,
     this.categoryPath,
     this.isActive,
@@ -43,6 +45,7 @@ class AdminProduct {
       name: (json['name'] ?? '').toString(),
       canonicalName: json['canonicalName']?.toString(),
       normalizedName: json['normalizedName']?.toString(),
+      ownerId: ((json['owner'] as Map<String, dynamic>?)?['id'] as num?)?.toInt(),
       categoryId: (json['categoryId'] as num?)?.toInt(),
       categoryPath: names.isEmpty ? null : names.join(' > '),
       isActive: json['isActive'] as bool?,

flutter/lib/features/admin/domain/pending_product.dart

@@ -3,6 +3,8 @@ class PendingProduct {
   final String name;
   final String? canonicalName;
   final DateTime? createdAt;
+  final int? ownerId;
+  final int? categoryId;
   final String? categoryPath;
   final String? ownerUsername;
 
@@ -11,6 +13,8 @@ class PendingProduct {
     required this.name,
     this.canonicalName,
     this.createdAt,
+    this.ownerId,
+    this.categoryId,
     this.categoryPath,
     this.ownerUsername,
   });
@@ -45,6 +49,8 @@ class PendingProduct {
       createdAt: json['createdAt'] == null
           ? null
           : DateTime.tryParse(json['createdAt'].toString()),
+      ownerId: (owner is Map<String, dynamic>) ? (owner['id'] as num?)?.toInt() : null,
+      categoryId: (json['categoryId'] as num?)?.toInt(),
       categoryPath: parts.isEmpty ? null : parts.join(' > '),
       ownerUsername: owner is Map<String, dynamic>
           ? owner['username']?.toString()