swarmexec v1.1.1 — port-forward UI polish

Client-side only; no wire-protocol change, so a v1.1.0 agent stays
compatible and does not need redeploying.

- ui: the tree marker now shows local→remote (e.g. "19090→3002"), so the
  container port a forward lands on is visible on the main view, not only
  in the Forwards tab.
- ui: the forward-detail overlay is left-aligned (it reused a modal that
  centered each line, shearing the key/value block).
- ui/cli: surface how to stop a forward — the CLI prints "press Ctrl-C to
  stop", and the detail overlay shows "d stop · Esc close" and accepts d.