mecatui: customizable status line

What

Claude Code lets the operator customize the status line (the persistent footer strip) via a statusLine settings entry — either a shell command whose stdout is rendered, or a structured layout of segments (model, cwd, git branch, context usage, cost, etc.).

mecatui's footer is a fixed, hardcoded layout. The operator cannot add, remove, reorder, or restyle what it shows.

Why

• The footer is the one always-visible surface; different operators want different facts there (git branch, token spend, active environment, time, a custom shell snippet).
• This is a pure client-side concern — mecatui renders from relayed proto Events plus its own session state, so no engine/proto change is needed for a settings-driven layout.

Shape (proposal, not settled)

• A statusLine (or footer) entry in the mecatui settings file.
• Two tiers, cheapest first:
  1. Segment toggles/order — pick from the facts mecatui already renders (model, session, cwd, git, usage).
  2. Shell-command segment — run an operator command, render its stdout (bounded, scrubbed, timeout-bounded like hooks).
• Live-reload should compose with #456 (live-reload mecatui settings).

Related

• #456 — live-reload mecatui settings without restart
• #555 — surface abstraction for mecatui modals/overlays (the footer is not a modal, but shares the render/settings plumbing)

Start by locating mecatui’s footer rendering and settings-loading entry points; no specific files or tests are named in the issue. Review the existing footer facts and the live-reload work in #456 before settling the configuration shape. Done means an agreed, tested settings-driven layout, including defined behavior for segment ordering and any shell-command output.