A dsh launch whose config failed validation returned the user to a broken
shell: typing was invisible and the next command was mangled by a stray
Device Attributes reply (1;2;4cecho ...).
The Loader mounts entries concurrently, so ui-tui can already hold the
terminal (raw mode, bracketed paste, keyboard protocol, plus an in-flight
DA query) when a sibling entry rejects on its own config. installFailLoud
wrote its diagnostic and exited immediately, so nothing disposed the tree
and ProcessTerminal.stop() never ran.
Give installFailLoud an optional release teardown, awaited between the
diagnostic and the exit and bounded by FAIL_LOUD_RELEASE_TIMEOUT_MS. The
TUI launcher passes one that disposes the root context, reaching the same
shutdown() the /exit path already uses (drainInput() + ui.stop()). The
context is captured in boot()'s prepare hook because the rejection arrives
while boot() is still in flight.
Bins that pass no release keep the previous behavior exactly.