fix(workaround): relax Pydantic data model constraint

All hosts have minimal differences in the fields they use for customizing running the mcp servers.

- No good scalable solution to define per-host data models for now.
- Allow all extra field to make sure we are not canceling existing customized MCP configuration in hosts.

Author: LittleCoinCoin

hatch/mcp_host_config/models.py

@@ -29,7 +29,7 @@ class MCPHostType(str, Enum):
 class MCPServerConfig(BaseModel):
     """Consolidated MCP server configuration supporting local and remote servers."""
 
-    model_config = ConfigDict(extra="forbid")
+    model_config = ConfigDict(extra="allow")
 
     # Server identification
     name: Optional[str] = Field(None, description="Server name for identification")