Summary

• restore account-switch blocking for persisted usage-limit hints that do not include reset timestamps
• keep the new typed primary/secondary limit behavior from the multi-auth usage snapshot fix
• add a regression test covering a second ChatGPT account blocked only by a usage-limit hint

Validation

• cargo test -p code-core skips_chatgpt_accounts_blocked_by_hint_without_reset
• cargo test -p code-core typed_usage_limit_snapshot_blocks_only_that_account
• ./build-fast.sh
• ./pre-release.sh

Auto-review was right: without this fallback, a hint-only limit persisted across restart could stop blocking an account in multi-auth fallback.