refactor: reorganize message handling for better type safety and clarity (#239)

* refactor: improve typing with memory stream type aliases

Move memory stream type definitions to models.py and use them throughout
the codebase for better type safety and maintainability.

GitHub-Issue:#201

* refactor: move streams to ParsedMessage

* refactor: update test files to use ParsedMessage

Updates test files to work with the ParsedMessage stream type aliases
and fixes a line length issue in test_201_client_hangs_on_logging.py.

Github-Issue:#201

* refactor: rename ParsedMessage to MessageFrame for clarity

🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>

* refactor: move MessageFrame class to types.py for better code organization

🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>

* fix pyright

* refactor: update websocket client to use MessageFrame

Modified the websocket client to work with the new MessageFrame type,
preserving raw message text and properly extracting the root JSON-RPC
message when sending.

Github-Issue:#204

* fix: use NoneType instead of None for type parameters in MessageFrame

🤖 Generated with [Claude Code](https://claude.ai/code)

* refactor: rename root to message

tests/issues/test_192_request_id.py

@@ -11,6 +11,7 @@ from mcp.types import (
     JSONRPCMessage,
     JSONRPCNotification,
     JSONRPCRequest,
+    MessageFrame,
     NotificationParams,
 )
 
@@ -64,7 +65,9 @@ async def test_request_id_match() -> None:
             jsonrpc="2.0",
         )
 
-        await client_writer.send(JSONRPCMessage(root=init_req))
+        await client_writer.send(
+            MessageFrame(message=JSONRPCMessage(root=init_req), raw=None)
+        )
         await server_reader.receive()  # Get init response but don't need to check it
 
         # Send initialized notification
@@ -73,21 +76,27 @@ async def test_request_id_match() -> None:
             params=NotificationParams().model_dump(by_alias=True, exclude_none=True),
             jsonrpc="2.0",
         )
-        await client_writer.send(JSONRPCMessage(root=initialized_notification))
+        await client_writer.send(
+            MessageFrame(
+                message=JSONRPCMessage(root=initialized_notification), raw=None
+            )
+        )
 
         # Send ping request with custom ID
         ping_request = JSONRPCRequest(
             id=custom_request_id, method="ping", params={}, jsonrpc="2.0"
         )
 
-        await client_writer.send(JSONRPCMessage(root=ping_request))
+        await client_writer.send(
+            MessageFrame(message=JSONRPCMessage(root=ping_request), raw=None)
+        )
 
         # Read response
         response = await server_reader.receive()
 
         # Verify response ID matches request ID
         assert (
-            response.root.id == custom_request_id
+            response.message.root.id == custom_request_id
         ), "Response ID should match request ID"
 
         # Cancel server task