read_inbox now requires explicit MarkRead (default false). Worker-queue callers
opt in. Resolves bugs-synapbus #30674 where consecutive identical calls returned
0 the second time and produced inconsistent views with the claim/process/done
loop and StalemateWorker.
failTimedOutProcessing UPDATE now re-checks claimed_at < cutoff so a fresh
re-claim between SELECT and UPDATE can't be stomped to failed.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>