P15.3 — PC-Web Parity Release
- Restored cloud account sync (username auth) with verified cross-device e2e (PC ⇄ Web, additive union merge)
- Rebuilt Account & Sync dialog with truthful sync states and full keyboard/focus lifecycle
- BCP-47 language-code boundary at setLanguage (zh-CN/ja-JP/... programmatic switching)
- Collapsed-sidebar gutter reclaim across all learning workspaces (86px dead band → 16px)
- Updater failure recovery + clean portable runtime proof (P14.x line)
- Web public edition now mirrors this architecture: https://study-tools-web-pages.pages.dev
- New PC↔Web synchronization contract gates every future shared-scope release
Signed with Ed25519 key prod-key-2026-r42. The updater verifies release-manifest.json.sig before any download; nothing downloads or applies without explicit user confirmation.