Stage 56 — PWA Storage & Resilience

One-stage test for PWA storage diagnostics, install-state detection and public-cache health. No database changes and no SQL import.

1. PASS — PWA cache version v8 is present.
2. PASS — Storage resilience diagnostics are present.
3. PASS — Installed-PWA state detection is present.
4. PASS — Public PWA cache health check is present.
5. PASS — API and private application routes remain excluded from PWA caching.