The reader funnels both chat and high-volume _sbx:data terminal frames
through one channel, and the UI loop redraws after handling a single frame
per turn — so on a viewer's side each chat message queued behind hundreds
of sandbox frames only surfaced one-per-redraw, making chat appear to
buffer/stall whenever a shared shell was scrolling output.
Drain a bounded burst (up to 256) of ready frames per turn via a new
drain_ready() helper, keeping chat latency bounded no matter how hard the
sandbox is streaming. Add regression tests covering FIFO/cap behavior and
chat surfacing within a few turns under flood.
Also add connect.sh: a join helper with a default port that keeps the room
password in RAM only (no-echo prompt or env var, never written to disk).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
