v0.85.2

Fixed

• Narrowing the window no longer clears the screen (ADR-0094). Pictures
  on the screen — mermaid diagrams and /show — stay, and no empty screens
  pile into the scrollback: v0.85.0's known limitation. A shrink now erases
  only the rows the input frame gained by re-wrapping. Measured on iTerm2 and
  kitty, by hand, driven and by mouse drag: no stale copy of the box, no
  empty rows, no lost line, the picture kept. Before, the same drag left
  565 empty rows and seven copies of the box in iTerm2's scrollback, and
  kitty lost every line and picture that was on the screen.

Changed

• The input box's rows end where their text ends (ADR-0094).
  They were drawn padded with spaces to the full width, so a repaint during
  a window resize — the cursor blink is one — wrote a row as wide as the old
  width into a narrower terminal and left a stale copy of the box behind.
  The input line's highlight still spans the window, drawn as an erase to
  the edge in its colour, and now follows the window's width.
• While the window's width is changing, the frame below the conversation
  is drawn short (ADR-0094) — every row cut to 19 cells until no report
  changing the width has come for 400 ms, then drawn in full. iTerm2 tells the program its new
  width only about every 200 ms while it moves its screen continuously, so
  a full-width row drawn in between could land wider than the screen.

Development

• make resizeprobe (ADR-0094) — the instrument the fix above was
  chosen with. It runs the real TUI in a terminal, narrows and widens the
  window, and counts stale frames, empty rows and lost history from the
  terminal's own text. -auto kitty|iterm2 does it in a new window with
  nobody at the keyboard — exact widths, a mouse drag (-drag), screenshots
  and a trace of every flush — and -drive does the text part under tmux.