fix(career): passport review polish — a11y semantics + seen-state guard (#937)

CodeRabbit follow-up on #936 (the one Major — overlay outside the click
root — was verified false: the host mounts every screen.html root inside
#plugin-career, ✕-close confirmed working live):

- Tabs: aria-selected/aria-controls + role=tabpanel/aria-labelledby.
- Book overlay: role=dialog + aria-modal + aria-label; focus moves to
  the close button on open and returns to the opener on close.
- seenBadges(): guard non-object JSON so a corrupt stored value cannot
  throw on every passport refresh (covered by a new corruption test).
- Fresh-session suppression test (badge seen → no re-notification).
- Stylelint declaration-empty-line-before nit in .pp-stamp.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

CHANGELOG.md

@@ -56,6 +56,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   engine (`app.js`, `highway.js`, `playSong`, `showScreen`, the capability registry).
 
 ### Fixed
+- **Career passports review polish** — the passport tabs and book overlay carry
+  proper ARIA semantics (`aria-selected`/`aria-controls`/`tabpanel`;
+  `role="dialog"` + `aria-modal` with focus moved to the close button on open
+  and restored on close), and a corrupt stored seen-badges value (e.g. a stray
+  `"null"`) can no longer throw on every passport refresh.
 - **The packaged desktop app could not start (`ModuleNotFoundError: No module named
   'appstate'`).** feedback-desktop's `scripts/bundle-slopsmith.sh` copies a *hardcoded
   list* of core files into the app bundle — `server.py`, `VERSION`, `lib/`, `data/`,