Fix stuck adapter_queue jobs (ASTS/IRE/IREN stuck pending forever):
1. fetchSpec early-return paths (cooldown checks) now update job status
to 'backoff' with last_attempt set and 30s backoff_until, instead of
returning without any status change. Prevents jobs from being
re-processed every drain cycle indefinitely.
2. Wrap adapter.fetchOne() in 30s Promise.race timeout. A hung HTTP
request no longer blocks the entire per-source promise chain
forever, preventing all subsequent jobs for that source.
Also includes corridor/confluence feature, tiered quote schedules,
cache improvements, and HoldingsBookView refinements.