When the main agent uses a named custom provider (custom:<name>),
resolve_runtime_provider correctly resolves the base_url and api_key.
But the auxiliary client re-resolves from the bare 'custom' provider
name, losing the provider identity. The bare 'custom' falls back to
OpenRouter, which _resolve_custom_runtime() then rejects — leaving all
auxiliary tasks (title gen, compression, vision, session search, etc.)
with no credentials.
Fix: when resolve_provider_client receives a main_runtime dict
containing concrete base_url + api_key, use it directly instead of
re-resolving. The main agent already solved provider resolution;
the auxiliary client just needs to reuse its answer.
Closes#45472
Ray
92da7a9970