The OR pattern inside backend-size used (or (multiple-value-bind ...)
...), but multiple-value-bind only returns the primary value of its
body. When the env-var shortcut was removed, both calls to backend-size
(the cols nth-value 0 and rows nth-value 1) returned the same primary
value, making rows always nil.
Restructure with nested multiple-value-bind/values chains so both
return values propagate correctly through all fallback stages.
Also remove MY_TERM_COLS/ROWS env-var pre-check — it returned stale
startup dimensions after terminal resize.
Amr Gharbeia
de1864bd94