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>

job-tracker-ui/src/components/SettingsView.tsx

@@ -24,6 +24,7 @@ import ImportExportJobs from "./ImportExportJobs";
 import GoogleAuthCard from "./GoogleAuthCard";
 import RulesSettingsCard from "./RulesSettingsCard";
 import BackupCard from "./BackupCard";
+import QuickCaptureCard from "./QuickCaptureCard";
 import AuthStatusCard from "./AuthStatusCard";
 import { ThemeModePref } from "../themePrefs";
 import { useI18n } from "../i18n/I18nProvider";
@@ -297,6 +298,8 @@ export default function SettingsView({
 
             <ImportExportJobs />
           </Paper>
+
+          <QuickCaptureCard />
         </Box>
       </TabPanel>