Fix layer violations and weird imports for docs.

Author: gspencergoog

packages/a2a_dart/lib/src/client/sse_transport.dart

@@ -2,16 +2,17 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+/// @docImport 'transport.dart';
+library;
+
 import 'dart:async';
 import 'dart:convert';
 
 import 'package:http/http.dart' as http;
 
-import '../../a2a_dart.dart' show Transport;
 import 'a2a_exception.dart';
 import 'http_transport.dart';
 import 'sse_parser.dart';
-import 'transport.dart' show Transport;
 
 /// An implementation of [Transport] that uses Server-Sent Events (SSE) for
 /// streaming communication.

packages/a2a_dart/lib/src/client/transport.dart

@@ -2,11 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:async';
-
-import '../../a2a_dart.dart' show A2AClient;
+/// @docImport 'a2a_client.dart';
+library;
 
-import 'a2a_client.dart' show A2AClient;
+import 'dart:async';
 
 /// An interface for sending and receiving messages to an A2A server.
 ///

packages/a2a_dart/lib/src/core/agent_capabilities.dart

@@ -2,10 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+/// @docImport 'agent_card.dart';
+library;
+
 import 'package:freezed_annotation/freezed_annotation.dart';
 
-import '../../a2a_dart.dart' show AgentCard;
-import 'agent_card.dart' show AgentCard;
 import 'agent_extension.dart';
 
 part 'agent_capabilities.freezed.dart';

packages/a2a_dart/lib/src/core/agent_extension.dart

@@ -2,14 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:freezed_annotation/freezed_annotation.dart';
-
-import '../../a2a_dart.dart' show AgentCapabilities;
+/// @docImport 'agent_capabilities.dart';
+library;
 
-import 'agent_capabilities.dart' show AgentCapabilities;
+import 'package:freezed_annotation/freezed_annotation.dart';
 
 part 'agent_extension.freezed.dart';
-
 part 'agent_extension.g.dart';
 
 /// A declaration of a protocol extension supported by an agent.

packages/a2a_dart/lib/src/core/agent_interface.dart

@@ -2,14 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:freezed_annotation/freezed_annotation.dart';
-
-import '../../a2a_dart.dart' show AgentCard;
+/// @docImport 'agent_card.dart';
+library;
 
-import 'agent_card.dart' show AgentCard;
+import 'package:freezed_annotation/freezed_annotation.dart';
 
 part 'agent_interface.freezed.dart';
-
 part 'agent_interface.g.dart';
 
 /// Defines the transport protocols that can be used for A2A communication.

packages/a2a_dart/lib/src/core/agent_provider.dart

@@ -2,14 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:freezed_annotation/freezed_annotation.dart';
-
-import '../../a2a_dart.dart' show AgentCard;
+/// @docImport 'agent_card.dart';
+library;
 
-import 'agent_card.dart' show AgentCard;
+import 'package:freezed_annotation/freezed_annotation.dart';
 
 part 'agent_provider.freezed.dart';
-
 part 'agent_provider.g.dart';
 
 /// Represents the service provider of an agent.

packages/a2a_dart/lib/src/core/agent_skill.dart

@@ -2,14 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:freezed_annotation/freezed_annotation.dart';
-
-import '../../a2a_dart.dart' show AgentCard;
+/// @docImport 'agent_card.dart';
+library;
 
-import 'agent_card.dart' show AgentCard;
+import 'package:freezed_annotation/freezed_annotation.dart';
 
 part 'agent_skill.freezed.dart';
-
 part 'agent_skill.g.dart';
 
 /// Represents a distinct capability or function that an agent can perform.

packages/a2a_dart/lib/src/core/part.dart

@@ -2,11 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:freezed_annotation/freezed_annotation.dart';
-
-import '../../a2a_dart.dart' show Message;
+/// @docImport 'message.dart';
+library;
 
-import 'message.dart' show Message;
+import 'package:freezed_annotation/freezed_annotation.dart';
 
 part 'part.freezed.dart';
 part 'part.g.dart';

packages/a2a_dart/lib/src/server/handler_result.dart

@@ -2,11 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:async';
-
-import '../../a2a_dart.dart' show RequestHandler;
+/// @docImport 'request_handler.dart';
+library;
 
-import 'request_handler.dart' show RequestHandler;
+import 'dart:async';
 
 /// A sealed class representing the result of a [RequestHandler].
 sealed class HandlerResult {}