Scope remote code ownership to normalized hoster and account identities while retaining title-only recovery serialization and canonical Unicode title matching.
Mark post-upload ambiguity and duplicate identities as uncertain so retries, account fallback, and later same-title jobs fail closed instead of reporting unsafe success.
Acquire recovery title leases before hoster and global semaphores, revalidate failed-account overrides before upload, and clear claim state at batch boundaries.
Add deterministic concurrent coverage for same-code rejection, distinct-code parallel success, uncertainty propagation, semaphore fairness, account isolation, Unicode equivalence, and registry lifetime.
Share account-scoped recovery claims with login uploader instances and serialize same-title recovery windows. Reserve direct and recovered file codes consistently, reject reused identities, and cover concurrent singleton recovery plus distinct-code and parallel-success cases.
Serialize recovery windows per hoster account and normalized filename, reserve remote codes across the batch, and keep cancellation responsive while waiting. Reject semantic and malformed file-list baselines instead of treating them as empty accounts, with focused regression coverage and release allowlist updates.