- terminal: on workspaceId change call terminal.clear() and
terminal.reset() so the previous workspace's scrollback is wiped
before the new shell's output appears.
- terminal: set macOptionIsMeta: false. With the default (true),
Mac Option+key sequences (e.g. Option+[ emits ESC) leak a literal
0x1b into the shell's stdin, which crashes downstream REPLs like
Python's with "invalid non-printable character U+001B".