feat: add AI recommendations flow for tenders

Implement company AI onboarding/recommendation models, services, repository, and tender UI integration with supporting tests.

Co-authored-by: Cursor <cursoragent@cursor.com>

lib/data/services/model/onboarding_response/onboarding_response.dart

@@ -0,0 +1,24 @@
+// ignore_for_file: invalid_annotation_target
+
+import 'package:freezed_annotation/freezed_annotation.dart';
+
+import '../error/error_model.dart';
+import '../onboarding_data/onboarding_data.dart';
+
+part 'onboarding_response.freezed.dart';
+part 'onboarding_response.g.dart';
+
+/// Standard API envelope for `POST /api/v1/onboarding`.
+@freezed
+abstract class OnboardingResponse with _$OnboardingResponse {
+  @JsonSerializable(explicitToJson: true)
+  const factory OnboardingResponse({
+    @JsonKey(name: 'data') required OnboardingData? data,
+    @JsonKey(name: 'error') required ErrorModel? error,
+    required String? message,
+    required bool? success,
+  }) = _OnboardingResponse;
+
+  factory OnboardingResponse.fromJson(Map<String, dynamic> json) =>
+      _$OnboardingResponseFromJson(json);
+}