Final PRD 0020 chunk. `x` on a focused agents-pane row tears
down the selected bottle if the dashboard owns it (started via
the chunk-2 `n` flow): pops `(cm, bottle, identity)` from the
main loop's bottles map, snapshots the transcript best-effort,
calls `cm.__exit__(None, None, None)` to drive the existing
compose-down + network-remove sequence, then `settle_state` to
honor any pre-existing preserve marker.
On a non-owned slug (discovered via `list_active_slugs` but not
in the dashboard's bottles dict — i.e., previous-dashboard or
external `./cli.py start` bottle), `x` is a no-op with a status
hint pointing at `./cli.py cleanup`. Matches the PRD's
cross-dashboard re-attach model: the dashboard can re-attach
either kind, but can only tear down its own.
The PRD's chunk 5 ("quit-cleanup") is satisfied by the existing
no-op behavior of `q` — per the user's resolved-question
answer, quit leaves bottles running unchanged. No code change
needed for that.
Footer surfaces `[x] stop`. 465 unit tests pass (1 new for the
non-owned no-op path; the owned path is integration territory
because it drives a real compose-down).