shell.online v0.7.2

Removes the separate black rectangle beneath the fitted terminal on mobile. xterm's unused viewport now matches the active terminal background in both dark and light themes.

This includes the v0.7.1 fixed 80x24 shared-grid behavior: desktop, mobile, read-only, and local viewers scale independently without deforming one another's TUI.

All binaries and install metadata are covered by SHA256SUMS.