On an incoming call the desktop window blinked continuously (FileNotFoundException
from SoundPlayer.start writing into a missing ...\Temp\simplex).
Root cause: Files.desktop top-level val initializers run in any process that
touches the facade class, including a transient second instance (which reaches
acquireSingleInstance -> dataDir). Two of them deleted shared state used by the
running primary:
- tmpDir had .also { deleteOnExit() } - the second instance's normal exit deleted
...\Temp\simplex, so the primary then failed to write call sounds/recordings.
- preferencesTmpDir had .also { deleteRecursively() } - the second instance's
<clinit> wiped configPath\tmp (same anti-pattern, firing even earlier).
Make both declarations pure and do the destructive cleanup in Main, past the
single-instance check, so only the owning instance performs it (preferencesTmpDir
kept early, before any settings write). The remaining val-initializer side effects
are idempotent creations (mkdirs) that destroy nothing and are left in place.
