fix(test): pass explicit args=[] to StdioTransport for stdio fixture

The fastmcp docs show `args` as optional but the installed
StdioTransport.__init__ has it as a required positional. CI failed
with TypeError on the first stdio test run; explicit empty list
fixes it.

(The unit-test failure on the same CI run — test_kill_signal_diagnostics
PyMemoryView buffer flake — is unrelated to this PR; that test file
was not touched and other PRs' runs on the same runner image pass it
fine. Flagging here as a known unrelated flake; will not address in
this PR.)

Author: kingpanther13

tests/src/e2e/conftest.py

@@ -1325,7 +1325,10 @@ async def stdio_mcp_client(
         "HA_MAX_RETRIES": "1",
     }
 
-    transport = StdioTransport(command="ha-mcp", env=env)
+    # `args` is a required positional in this fastmcp version (the docs
+    # show it as optional, but the installed StdioTransport.__init__
+    # disagrees — pass an explicit empty list).
+    transport = StdioTransport(command="ha-mcp", args=[], env=env)
     client = Client(transport)
     async with client:
         logger.debug("🔗 FastMCP client connected (stdio subprocess transport)")