* server: clear a stale message when an agent starts a new turn

SessionStart left "session started" on the row for the whole turn. A move into Working without its own message now clears the previous one, so rows show the run state until the turn speaks.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* gui: readable light terminals, leading, and clean pane titles

Light panes get their own ANSI inks (all but the greys >= 4.5:1 on white, unit-tested) instead of GNOME's dark-pane palette, rows get 1.1x leading, and pane titles drop the shell's user@host: prefix.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs: specify the craft pass

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* gui: keep remote hosts in pane titles

A user@host: prefix is dropped only for the local machine, so an SSH session still says where it runs; space-less \u@\h:\w prompts are handled too.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

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Co-authored-by: Lucenx9 <185146821+Lucenx9@users.noreply.github.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>