A workspace model shared publicly could be used by any user even when its
base model was private. Unregistered base models (no row in the model
table) are admin-only for direct use — get_filtered_models hides them from
non-admins and check_model_access rejects them — but has_base_model_access
treated a missing row as "no ACL" and allowed the chained request through.
has_base_model_access now takes the caller's role and only allows an
unregistered base model hop for admins, so a shared preset can no longer
reach a base model the caller could not use directly. Registered base
models keep their existing grant-based enforcement.
Claude-Session: https://claude.ai/code/session_018toPfJW1hMXAhokGaL43Ep
Co-authored-by: Claude <noreply@anthropic.com>
