The composer accepts three encodings for Shift+Enter (kitty CSI-u, the
legacy \x1b[13;2~ form, and a bare LF from the iTerm2 mapping e.g. Claude
Code's /terminal-setup). The /tree selector only handled the kitty form and
silently routed a bare LF into the plain-Enter branch, so summarize-and-
switch never fired for those terminals.
Mirror the composer: fall through a bare LF to summarize-and-switch while
plain CR (or the decoded Enter key) still does a plain switch.
Fixes#8821
re2zero
73e0366121