A command longer than the input field used to clip silently at the
right edge, hiding the cursor and the command tail. Now the single
logical input line scrolls horizontally to keep the cursor in view,
with muted `<` / `>` markers at the reserved edge columns signalling
hidden content on either side.
The offset is a pure function of (line length, cursor column, field
width, previous offset) — input_scroll_offset — so the view only moves
when the cursor would leave the window, and one column is held on each
side for the markers so a marker never hides the cursor. The stored
App::input_scroll_offset resets when the buffer is replaced wholesale
(submit, history recall). The ADR-0027 6-column indicator reserve is
preserved.
Tests: pure-offset cases, tail-visible + head-visible render checks,
and the reset-on-submit/history check. One layout snapshot now shows a
long command's tail instead of its clipped head.
claude@clouddev1
e0b9470feb