fix: make launcher_type optional in launcher_create for backwards compatibility

Author: rokroskar

bases/renku_data_services/mcp_api/server.py

@@ -532,8 +532,8 @@ async def launcher_create(
         resource_class_id: Annotated[int, Field(description="Resource class ID (from resource_classes())")],
         environment: Annotated[dict[str, Any], Field(description="Environment definition dict")],
         launcher_type: Annotated[
-            str, Field(description="'interactive' for sessions, 'non_interactive' for jobs")
-        ] = "interactive",
+            str | None, Field(description="'interactive' for sessions, 'non_interactive' for jobs — omit for older API versions")
+        ] = None,
         description: Annotated[str, Field(description="Optional description")] = "",
     ) -> dict[str, Any]:
         """Create a session launcher. Always call resource_classes(cpu=..., memory=...) first.
@@ -560,8 +560,9 @@ async def launcher_create(
             "name": name,
             "resource_class_id": resource_class_id,
             "environment": environment,
-            "launcher_type": launcher_type,
         }
+        if launcher_type is not None:
+            body["launcher_type"] = launcher_type
         if description:
             body["description"] = description
         return _launcher_summary(await _api(ctx, "POST", "/session_launchers", body))