Function persist_session_id 

pub(crate) fn persist_session_id(
    block_id: &str,
    sid: &str,
    mstore: &Option<Arc<Store>>,
    event_bus: &Option<Arc<EventBus>>,
)

Persist a newly captured session ID to block metadata and broadcast the waveobj:update event so the frontend reflects the change immediately.

Every controller that captures a session id goes through this one path (persistent/stdout_reader.rs and stderr_reader.rs, subprocess/host_spawn.rs and container_spawn.rs, acp.rs, app_server_controller.rs); ACP used to only set inner.session_id in memory.

Also writes through to the matching db_agent_instances row’s session_id column (SPEC_PANE_CLOSE_REOPEN_CONTINUITY_GUARANTEE_2026_07_27.md §4.1). Without this, that column was set to "" at instance creation and never updated again in production — ListRecentSessionsCommand prefers the local row over the shared registry whenever both exist, so the “My Agents” picker’s reattach flow (AgentPicker.tsx’s handleReattach) was handed an empty session id even mid-session, and — per agent-model.ts’s own documented invariant that an empty continueSessionId clears agent:sessionid on the new block — silently started a genuinely fresh conversation instead of resuming. Best-effort: logs and continues on failure, since the block-meta write above (the live-turn source of truth) already succeeded.

No-ops silently when mstore is None (e.g. in unit tests that don’t wire up a store).