Function parse_persisted_session_agent_model 

pub fn parse_persisted_session_agent_model(
    agent_value: Option<&str>,
    model_value: &str,
) -> AgentSelection

Parses one persisted session agent/model pair without deriving the agent from the model when the saved agent kind is available.

Existing databases did not persist agent, so rows with a missing or invalid agent value fall back to a compatibility provider inferred from the persisted model string. Ambiguous raw gemini-* rows default to Antigravity because direct Gemini support had been removed before the new agent column was introduced.