Function open_agent_panes 

pub(crate) fn open_agent_panes(
    store: &Store,
    block_ids: &[String],
) -> Vec<AgentOpenPane>

Where each of block_ids is open: its agent, tab, and the windows showing its workspace. The agent is resolved like the rest of srv resolves a block’s agent (instance_get_active_for_block: agentId, the legacy agent:id, a template-launched row, the latest launch on the block) so a pane from an older build is not reported closed (Codex P1 on #4127); the raw meta id is the fallback when that finds no row. Blocks with no resolvable agent or no parent tab are skipped. Workspaces and windows are read once for the whole list.