Port of the grr client of tai.py: client, SSE stream, session, store, router, shell, views,
chat, panes, file viewer and the unix control socket; GrrTui::run is the --tui entry.
Verified against tai.py --tui on a real grr server over a pty: 236 steps, screen text and
per-cell styles identical except clocks, spinner frames and server-made ids.
docs/tui.md holds the symbol table and gaps, docs/wiring/tui.md the integrator hooks.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>