Save and resume working state checkpoints. Captures git state, decisions made,
and remaining work so you can pick up exactly where you left off — even across
Conductor workspace handoffs between branches.
Use when asked to "checkpoint", "save progress", "where was I", "resume",
"what was I working on", or "pick up where I left off".
Proactively suggest when a session is ending, the user is switching context,
or before a long break. (gstack)