pub fn validate_image_fallback_for_session(
session: &Session,
image_fallback: Option<&ImageFallbackConfig>,
_model_name: &str,
vision_override: Option<bool>,
) -> Result<(), String>Expand description
Validate images after resolving the provider and exact executing model. Explicit support bypasses the independent legacy fallback; missing support retains its opt-in policy. Explicit false uses transient ViewImage references; the HTTP host separately validates the explicit auxiliary target configuration.