Three follow-up fixes from the PR review pass:
- Follower callers (sharing an in-flight cascade) now race their own
abortSignal against the leader's promise, so a cancelled stream is
no longer blocked on the leader's lifecycle.
- Pre-aborted entry into autoLoadSmallestModel bails before the
"Loading a model..." toast fires, avoiding a flash for abort-then-
send sequences.
- Fallback-gate abort path now returns blockedByTrustRemoteCode:false
(matching the early-abort blocks at the loop bodies). Avoids
surfacing "Enable custom code" when the real outcome was an abort.
8cfd4a5a6c