fix(app-boot): keep the fail-loud exit fatal while the terminal is released

Review of the previous commit found two defects in the release path, both
reproduced against the implementation:

- The timeout guarding a never-settling release was unref'ed. An
  unhandledRejection listener suppresses Node's default fatal exit, so with
  nothing else referenced the process reached an empty event loop and exited
  0 on the very failure it was reporting. Keep the timer referenced and clear
  it once the race settles.

- The handler uninstalled itself before awaiting the release. A second
  concurrent rejection then became uncaught and killed the process
  mid-teardown, stranding exactly the terminal state this restores. Replace
  the uninstall with a latch: the first rejection is the reported one, and
  later rejections (teardown's own included) fall through to the pending exit.

Add the PTY regression the fake-process tests cannot express: boot the shipped
tree over a fixture whose llm-pi-ai providers value is list-shaped, expect exit
1, and assert the captured bytes carry both the diagnostic and ESC[?2004l.
Against the pre-fix source the stream ends at ESC[?2004h ESC[>7u ESC[?u ESC[c
with no reset and the case fails, so it pins the actual bug.

Split the two-shape formatting test into one install per case; a latched
handler reports once by design.

packages/ui/app-boot/README.md

@@ -21,7 +21,7 @@ Shared boot glue for the app bins ([`dsh`](../../../apps/cli/README.md), [`dsh-c
 
 Two Loader failure classes require separate guards because tree settlement propagates neither to its caller. A failed plugin import leaves a fiber-less entry that `assertEntriesLoaded` turns into a `boot()` rejection naming every unresolved plugin. A plugin callback or config failure leaves a failed fiber because `loader.await()` settles lifecycle tasks without propagating that error; `assertEntriesActivated` awaits the fiber explicitly and includes its original stack in the startup rejection. Before throwing, the audit marks those exact rejection reasons through one process checkpoint so `installFailLoud` coalesces Loader's duplicate notification while every unrelated unhandled rejection remains fatal.
 
-The Loader mounts entries concurrently, so a surface can already own the terminal when a sibling entry rejects: exiting straight from the handler would leave raw mode, bracketed paste, and the keyboard protocol set on the user's shell, and an in-flight terminal query's reply would land as literal text at the next prompt. A terminal-owning bin therefore passes `release` to dispose the tree — running that surface's own shutdown — before the exit commits. `dsh` captures the root context in `boot()`'s `prepare` hook rather than from its return value, because the rejection arrives while `boot()` is still in flight.
+The Loader mounts entries concurrently, so a surface can already own the terminal when a sibling entry rejects: exiting straight from the handler would leave raw mode, bracketed paste, and the keyboard protocol set on the user's shell, and an in-flight terminal query's reply would land as literal text at the next prompt. A terminal-owning bin therefore passes `release` to dispose the tree — running that surface's own shutdown — before the exit commits. `dsh` captures the root context in `boot()`'s `prepare` hook rather than from its return value, because the rejection arrives while `boot()` is still in flight. While a release is in flight the handler stays installed and latched: the first rejection is the reported one, and later rejections (teardown's own included) are swallowed rather than becoming uncaught and killing the process mid-teardown.
 
 Bare plugin specifiers in a config (`@deepseek-ai/dsh-*`, npm packages) resolve through the Cordis Loader's internal module loader. Repository bins install Loader's optional `node-addon-require-builtin` peer; external callers must supply it or install plugins where plain Node import resolution can find them. Relative specifiers resolve against the config directory without the native helper. The built `dsh-app-boot` artifact embeds the statically mounted Include implementation while leaving Loader external, so the include tree and host bind to one Loader peer. The `dsh` source launcher additionally maps manifest-declared workspace packages to their TypeScript source; its configuration gate requires every TUI/Web bare plugin to appear in the resolver manifest's `dependencies`. The bins' subprocess smokes exercise the internal-loader path, while this package's unit suite drives `boot()` in-process against configs with relative specifiers.