fix: graceful grace period before killing PTY on timeout

Bump ws from 8.20.0 to 8.21.0

When a command times out in runRaw, send Ctrl+C and wait a 3-second
grace period instead of immediately killing the PTY session. This
gives CLI tools that hang after completing (e.g. wispctl with TUI
spinners that don't cleanly exit) a chance to terminate gracefully.

If the sentinel appears during the grace window, the output is
captured and resolved successfully. Only kill the session if the
command remains stuck after the grace period.

This doesn't make things worse for legitimately slow commands —
the timeout already fired, and Ctrl+C was already sent — but it
saves tools that just need a nudge from being reported as failures.

Bumps [ws](https://github.com/websockets/ws) from 8.20.0 to 8.21.0.
- [Release notes](https://github.com/websockets/ws/releases)
- [Commits](https://github.com/websockets/ws/compare/8.20.0...8.21.0)

---
updated-dependencies:
- dependency-name: ws
dependency-version: 8.21.0
dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>