Local dev node tmux UTF-8 locale

Found while testing Task 10027. The local dev node (`./dc --profile node up`, tmux 3.3a in the container) runs `jaahd` with no `LANG`/`LC_ALL`. tmux then treats the daemon's client as non-UTF-8 and rewrites every TAB in `-F` output to `_`. So `console._find_live_clauded_window`'s tab-split `list-panes` listing parses empty, and a browser console never attaches to a live window: it shows "No session running on this slot" or tries to create one. Setting `LANG=C.UTF-8` on the `node` service fixed it at once. Suggestions: 1. Set a UTF-8 locale for the dev node's daemon (the `node` service environment in infra/local/docker-compose.yml, or Dockerfile.node). 2. Check whether packaged Linux nodes (`packaging/jaahd.service`) can hit the same thing: no locale in the unit plus a tmux that rewrites tabs. If they can, pass `-u` on every platform (session_user.tmux_cmd does this only on Windows) or set the locale in the unit. Out of scope: console features themselves. Done means: - On a fresh `./dc --profile node up`, a tmux window opened in a slot's path inside the node is attached by the browser console (screenshot), and `tmux -F` listings run by the daemon keep their tabs (a test or a one-line check in the container).

tmux_cmd now passes -u on every platform; dev-node image sets LANG=C.UTF-8. Tabs survive in -F output; browser console attached to a live slot window (screenshot). Quick gate green; PR #6920 merged; its deploy was superseded. Draft #10078 filed (dev-node jaah_home mismatch). Memory: used mem-25776; proposed none.