Function apply_srv_window_opened 

fn apply_srv_window_opened(
    wstore: &WaveStore,
    window_id: &str,
    workspace_id: &str,
) -> Result<(), Box<dyn Error>>

Phase E.5 — record/update a window’s workspace pointer on the persisted Window row. Idempotent: inserts if missing, updates if workspaceid differs, no-ops if identical.

Also keeps Client.windowids in sync — appends the new window_id when the Window row is freshly created. The legacy wcore::create_window_full path does this too; without it, the Window row exists but GetClientData / focus-order logic can’t see it. (codex P1 #619.)