iEduPortal PWA Stage 94
Academic Context Binding Page-Lifecycle Backpressure Hardening

Adds pagehide/pageshow lifecycle suspension, bounded pending mutation roots, safe queue collapse to a full-document scan under pressure, and lifecycle state controls. Preserves visibility-aware idle scheduling and dynamic DOM binding. No database changes.

Upgrade checker: upgrade/stage94.php
Service worker cache: ieduportal-pwa-v49
