ghostty-web 0.4.0 hands rows that scroll into view out of recycled WASM
page memory without clearing them, so after a tab or project switch the
new emulator showed the previous terminal's text (upstream #138). The fix
landed only in prereleases, so pin 0.4.0-next.20 and carry the local
block-glyph rendering patch over to the new dist file.
Verified in a production build: creating an emulator after disposing a
full one no longer exposes its rows, and switching between two projects
with live output in each keeps every terminal's content to itself.