GatewayRunner._prepare_inbound_message_text's "@" context-reference
block read self._model / self._base_url to resolve the model for
get_model_context_length_async. GatewayRunner never sets either
attribute (copy-pasted from HermesCLI in da44c196b, which does carry
self.model/self.base_url). Every message containing "@" raised
AttributeError inside the try block, silently swallowed by the
surrounding except Exception at debug level, so
preprocess_context_references_async never ran and @file:/@folder:/@diff/
etc. references passed through to the model unexpanded.
Fix: resolve model/provider/base_url via
self._resolve_session_agent_runtime(source=, session_key=,
user_config=), the same session-aware resolution the hygiene
compression block already uses a few hundred lines later in this file.
Also raise the swallow log from debug to warning (with exc_info at
debug) so a future regression here is visible instead of silent.
