When the inner-terminal env markers (KITTY_WINDOW_ID, GHOSTTY_RESOURCES_DIR,
WEZTERM_PANE, ITERM_SESSION_ID) leak into a tmux session, TERMINAL_ID
resolves to the inner terminal and notifyProtocol becomes OSC 9 / OSC 99.
sendNotification() wrote that raw OSC straight to stdout, but tmux does not
forward bare OSC 9/99 to the outer terminal and the bare sequence does not
flag tmux's own monitor-bell / monitor-activity — so a backgrounded omp pane
under the common tmux + kitty/ghostty/wezterm/iTerm2 stack had no signal at
all for completion or 'ask' blockage.
Under TMUX, OSC-protocol notifications are now wrapped in tmux's
\x1bPtmux;…\x1b\\ DCS passthrough envelope (so users with
allow-passthrough on still get the real desktop toast) and followed by a
\x07 BEL (so monitor-bell flags the window otherwise — the standard
'needs attention' workflow). The OSC 99 capability probe is wrapped the
same way so rich notifications keep working across tmux. Bell-protocol
paths are unchanged.
Fixes#3395
roboomp
28e1caec69