Adds a warn-severity modal notice targeting existing users who have the
MCP addon enabled. Communicates that OAuth 2.1 is now the recommended
auth method, static trek_ tokens are deprecated, and the toolset has
been significantly expanded. Priority 75 — slots between v3-journey and
v3-features in the upgrade modal sequence. Translations for all 15 languages.
Server-side notice registry with per-user condition evaluation (firstLogin,
existingUserBeforeVersion, addonEnabled, dateWindow, role, custom).
Notices are sorted by priority then severity, filtered against dismissals
stored in a new user_notice_dismissals table, and served via
GET /api/system-notices/active + POST /api/system-notices/:id/dismiss.
Client renders notices through a host component that partitions by
display type (modal / banner / toast). The modal renderer supports
multi-page pagination with directional slide transitions, keyboard
navigation, and correct dismiss-all semantics on CTA / X / ESC.
Dismissals are optimistic with a single background retry.
Includes 3.0.0 upgrade notices (v3-photos, v3-journey, v3-features),
onboarding welcome modal, and full i18n coverage across 15 languages.
The /journey route is addon-gated on both client and server.
Also includes: unit + integration test suites, registry integrity test
that validates action CTA IDs against client source, and technical
documentation in docs/system-notices.md.
jubnl