feat: quick-capture bookmarklet

One-click job capture from any posting, reusing the existing
jobimport/preview parser.

- AddJobModal accepts initialUrl and auto-imports once on open
- App reads a /?add=<encoded url> param, opens Add Job pre-filled, and
  strips the param from the address bar
- QuickCaptureCard in Settings offers a draggable bookmarklet (href set
  via ref since React blocks javascript: URLs) plus copyable code
- EN/NB translations; README feature note
- 2 frontend tests; full suite green (22 suites / 50 tests)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

README.md

@@ -12,6 +12,7 @@ Job Tracker is a simple, self-hosted app for tracking job applications with a Re
 - History/event trail per application (created, status changes, follow-up set, delete/restore)
 - Export jobs to JSON/CSV + daily scheduled JSON export
 - Optional “job import” preview from supported job sites (plugins) + optional translation to English
+- Quick-capture bookmarklet (Settings): opens `/?add=<page url>` to pre-fill Add Job from any posting
 - Optional local AI service for short/full descriptions
 - Optional Google sign-in (Google ID tokens) to protect the API