Route fields and list_subagent_models are now registered only by the
tool-subagent instance configured with modelSelectionSettings, which keeps
one fixed definition per composition for Web presets while headless and SDK
profiles return to their previous schemas. Discovery registers with that
instance instead of a separate list-models plugin entry, so the delegation
description never references an absent tool. modelSelectionSettings on a
provider that inherits the parent conversation now fails the mount.
Dudu-0223
764a51d507