fix(client): export TenantTransportDecorator and fix docstring

- Add TenantTransportDecorator to transports __init__.py __all__
  so it is importable via `from a2a.client.transports import
  TenantTransportDecorator` alongside the other transports.

- Fix send_message() docstring that incorrectly described it as
  a streaming method (copy-paste from send_message_streaming).

- Add test coverage for close() delegation and async context
  manager usage, verifying the decorator properly delegates
  lifecycle management to the underlying transport.

Author: 4444J99

src/a2a/client/transports/__init__.py

@@ -3,6 +3,7 @@
 from a2a.client.transports.base import ClientTransport
 from a2a.client.transports.jsonrpc import JsonRpcTransport
 from a2a.client.transports.rest import RestTransport
+from a2a.client.transports.tenant_decorator import TenantTransportDecorator
 
 
 try:
@@ -16,4 +17,5 @@
     'GrpcTransport',
     'JsonRpcTransport',
     'RestTransport',
+    'TenantTransportDecorator',
 ]

src/a2a/client/transports/tenant_decorator.py

@@ -43,7 +43,7 @@ async def send_message(
         *,
         context: ClientCallContext | None = None,
     ) -> SendMessageResponse:
-        """Sends a streaming message request to the agent and yields responses as they arrive."""
+        """Sends a non-streaming message request to the agent."""
         request.tenant = self._resolve_tenant(request.tenant)
         return await self._base.send_message(request, context=context)
 

tests/client/transports/test_tenant_decorator.py

@@ -127,3 +127,22 @@ async def mock_stream(*args, **kwargs):
         async for _ in decorator.send_message_streaming(request_msg):
             pass
         assert request_msg.tenant == tenant_id
+
+    @pytest.mark.asyncio
+    async def test_close_delegates_to_base(
+        self, mock_transport: AsyncMock
+    ) -> None:
+        """Test that close() is delegated to the underlying transport."""
+        decorator = TenantTransportDecorator(mock_transport, 'test-tenant')
+        await decorator.close()
+        mock_transport.close.assert_awaited_once()
+
+    @pytest.mark.asyncio
+    async def test_async_context_manager(
+        self, mock_transport: AsyncMock
+    ) -> None:
+        """Test that the decorator works as an async context manager."""
+        decorator = TenantTransportDecorator(mock_transport, 'test-tenant')
+        async with decorator as transport:
+            assert transport is decorator
+        mock_transport.close.assert_awaited_once()