fix(mcp-hosts): add explicit HTTP transport type for Claude URL-based co

Agent-Id: agent-4b2c06a4-05c6-47fd-84e7-4c704eb9fa05
Linked-Note-Id: 3d4ca15e-5b56-430d-9ea4-f5b77e4207aa

Author: LittleCoinCoin

hatch/mcp_host_config/adapters/claude.py

@@ -161,5 +161,11 @@ def serialize(self, config: MCPServerConfig) -> Dict[str, Any]:
         # Validate filtered fields
         self.validate_filtered(filtered)
 
-        # Return filtered (no transformations needed for Claude)
+        # Claude's URL-based remote configs should explicitly declare HTTP
+        # transport when callers omit the type field.
+        if "url" in filtered and "type" not in filtered:
+            filtered = filtered.copy()
+            filtered["type"] = "http"
+
+        # Return filtered Claude config
         return filtered