#33664 base red: the notify Watcher import is macOS-only (unused on Linux after #33406)

clippy (changed cmux-tui packages) fails on Linux for any PR that touches cmux-tui: error: unused import: notify::Watcher at crates/acpmux/src/login_env/watch.rs:15. #33406 moved Linux to inotify, so the trait import is used only by the non-Linux source (watcher.watch(...)). This puts the import under the same #[cfg(not(target_os = "linux"))].

One line, no behaviour change.

Agent session: agent session

🤖 Generated with Claude Code

---

^{Open in [code]smith · Need help on this PR? Tag @codesmith-bot with what you need.}

---

Summary by cubic

Fixes the Linux clippy failure unused import: notify::Watcher by gating the import behind #[cfg(not(target_os = "linux"))].

#33406 moved Linux to inotify, so the trait is imported only on other platforms. One line, no behavior change.