Cloud bootstrap ran inline before runApp: a throwing outbox open, outbox
prepare, Convex init or Supabase init left the app unshown, so a signed-out
desktop user could not reach a healthy local library. startCloud now runs
those steps, never throws, and on the first failure leaves the cloud off for
the run: auth sees no session and every sign-in answers with the reason, the
outbox stores read and write nothing, and a toast says so once the app is up.
The release-build check for ICARUS_CLOUD_ENVIRONMENT still stops startup.

The outbox boxes now open with Hive's crash recovery off. Recovery truncates
a box at its first bad frame, silently deleting the unsent work after it; a
corrupt outbox now stays on disk byte for byte and the cloud stays off.

A signed-out startup also no longer clears Convex auth it never set, which
opened the Convex socket for users who never asked for the cloud.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>