fix(mcp): cap the mcp dependency below 2.0

`mcp>=1.1.0` had no upper bound, so pip resolved mcp 2.0.0 the day it shipped
(2026-07-28) and MCPClient.connect() started returning False. The custom-agent
MCP harness went from green on 07-28 to red on 07-30 on the same branch with no
code change in between.

Matches the litellm pin two entries down. Lifting the cap is a real port of the
client to the 2.x API, not a version bump.

Author: kovtcharov

setup.py

@@ -214,7 +214,10 @@
             "bpy",
         ],
         "mcp": [
-            "mcp>=1.1.0",
+            # Capped below 2.0: mcp 2.0.0 (released 2026-07-28) breaks
+            # MCPClient.connect() — the custom-agent harness went red with no
+            # code change. Lift the cap in a change that ports the client.
+            "mcp>=1.1.0,<2.0",
             "starlette",
             "uvicorn",
         ],