The quick terminal caches its last-closed window frame per display so it
can restore the user's size when reopened. The cache entry was considered
valid whenever the current screen was the same size *or larger* than when
the frame was saved ("persist when screens grow"). This has led to a pattern
that was simply maddening. To wit:
That rule breaks across display changes. When an external display is
disconnected and later reconnected at a different resolution (common
after traveling with a laptop) the same display can come back larger
than when the frame was cached. The stale frame is still treated as valid
and restored, so the quick terminal no longer fills the screen (it appears
at a partial width/height). Because the cache is persisted, restarting
Ghostty does not clear it, and the user is slowly driven mad.
Only treat a cached frame as valid when the screen geometry matches
exactly (both backing scale factor and frame size). On any mismatch we
drop the entry and fall back to the configured quick-terminal-size. Manual
resizes are still remembered across toggles within a stable display
configuration.
Fixes the regression reported in #12348.
