A new surface spawned its shell immediately at the default 80x24, so the
shell (e.g. zsh + powerlevel10k) printed its first prompt before the GUI
fit-resized the panel. The post-print resize reflowed the grid, leaving the
prompt invisible until Enter and shifted by a line.
The surface actor now defers the child spawn: it waits for the first Resize
(spawning at that geometry) or, for headless/CLI surfaces that never attach a
GUI, falls back to the spec geometry after 250ms. Attaches received before
the spawn get an empty-grid snapshot plus a live subscription; pre-spawn
input is buffered and replayed. Adds two deterministic tests via `stty size`.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
vasyansk
a30ec1cc7f
