Function persist_define_content 

fn persist_define_content(
    wstore: &Store,
    agent_id: &str,
    cmd: &CommandAgentDefineData,
    now: i64,
)

Core logic for the agent.define command, shared by the WebSocket RPC handler and the HTTP service dispatch (("agent", "define") in service.rs). Persist system_prompt and env content blobs for a freshly created or updated agent definition. Errors are logged but not propagated — the definition row is already committed and the caller has already published agents:changed, so a content-write failure must not abort the response.