* fix: handle turbo shutdown in dev runner

* refactor: rely on effect child process shutdown

* refactor: inline turbo shutdown timeout

* add back sigint sigterm sighup handling

* refactor: tighten turbo signal forwarding

* refactor: inline dev runner errors

* fix: use detached false instead of manual signal forwarding

Effect defaults to detached: true on non-Windows, putting turbo in a
new process group where terminal signals (Ctrl+C) never reach it.
Setting detached: false keeps turbo in the same group, eliminating
the need for ~130 lines of manual signal forwarding.

* Update scripts/dev-runner.ts

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

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Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>