Python: [BREAKING] Standardize TypeVar naming convention (TName → NameT) (#3770)

* standardized typevar to use suffix T

* addressed copilot comments

python/packages/core/tests/core/conftest.py

@@ -27,7 +27,7 @@ from agent_framework import (
     ToolProtocol,
     tool,
 )
-from agent_framework._clients import TOptions_co
+from agent_framework._clients import OptionsCoT
 from agent_framework.observability import ChatTelemetryLayer
 
 if sys.version_info >= (3, 12):
@@ -135,11 +135,11 @@ class MockChatClient:
 
 
 class MockBaseChatClient(
-    ChatMiddlewareLayer[TOptions_co],
-    FunctionInvocationLayer[TOptions_co],
-    ChatTelemetryLayer[TOptions_co],
-    BaseChatClient[TOptions_co],
-    Generic[TOptions_co],
+    ChatMiddlewareLayer[OptionsCoT],
+    FunctionInvocationLayer[OptionsCoT],
+    ChatTelemetryLayer[OptionsCoT],
+    BaseChatClient[OptionsCoT],
+    Generic[OptionsCoT],
 ):
     """Mock implementation of a full-featured ChatClient."""