v3.0.71 — report clusters 2(singleton)/4/6/7
Consolidated-report follow-ups (over v3.0.68): instance singleton lock (cluster 2 follow-up) + settings-UI binds before backend checks with watchdog (cluster 4) [v3.0.69]; actionable, protocol-neutral error classification replacing 'An error occurred' (cluster 6) [v3.0.70]; search_emails confirmed already-live IMAP SEARCH + regression guard (cluster 7) [v3.0.71]. See CHANGELOG.