The settings search service is provided in the root injector, so the
watch it started on its first use had no owner: with a login shell that
never answers it kept asking every 30 s until the app quit, long after
the settings page or the command palette that needed the answer was
closed. A failed recheck also ended the watch as if it were a final
answer, hiding the Embedded MPV rows for the rest of the session.
The service now separates the two uses. `ensureEmbeddedMpvSupportLoaded()`
is a single request again, for the command palette. The settings page
calls `followEmbeddedMpvSupport()` and ends it when the page is destroyed.
Only a final answer is kept: after an inconclusive one or a failed
request the next use asks again, for the palette's player commands too.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>