B3 (HIGH): sora_generation_service.go - Add panic recovery to parallel
S3 URL fetching goroutines. Without recovery, a panic in GetAccessURL
would skip wg.Done() causing wg.Wait() to hang indefinitely.
B2 (MEDIUM): subscription_service.go:549 - Replace bare goroutine
with safego.Go() for consistent panic recovery pattern. All other async
calls in this file already use safego.
B4 (MEDIUM): admin/sora_handler.go - Change ClearUserStorage response
from 200 no-op to 410 Gone. The per-user storage quota was fully removed;
returning success was misleading to callers.
3a0ca7f57f