isMultiplexerSession() treats TMUX, STY, ZELLIJ, HERDR_ENV=1, the CMUX_*
markers and a tmux/screen TERM as authoritative, and routes rendering down the
path that cannot rebuild scrollback. Nine tests across four files assert the
destructive full-paint behavior and fail for anyone running the suite inside
tmux, screen, Zellij or CMUX.
component-render.test.ts already cleared HERDR_ENV for exactly this reason but
covered only one of the nine signals. Replace it with a shared helper that
clears the whole family and restores it afterwards, and call it from the other
three files.
Huang-404-Q
099ca42749