feat(ux): per-view subtitles, correspondence cross-links, mobile kanban, a11y

Continuing the product/UX review's deferred items:

- Every top-level view now gets a one-line subtitle under its title
  (Dashboard/Jobs/Kanban/Reminders/Correspondence/Gmail review) stating
  what that specific view is for, instead of navigation being the only
  signal of what each page does.
- Correspondence inbox and Gmail review queue cross-link to each other
  instead of being two unexplained flat sidebar items -- kept both nav
  entries (renaming/nesting risked breaking muscle memory) but made the
  relationship between them explicit in the UI itself.
- Kanban board switches to a horizontal scroll-snap row on phone-width
  viewports instead of stacking all 5 columns vertically, which meant
  a lot of scrolling to see anything past "Applied".
- Match-score ring gets an aria-label with the actual percentage --
  it was two nested decorative CircularProgress elements with no
  accessible text. (Keyboard-accessible status changes on kanban cards
  were already covered by the existing "..." menu -- no gap there.)

job-tracker-ui/src/i18n/translations.ts

@@ -18,6 +18,12 @@ export const translations = {
     home: "Home",
     analytics: "Analytics",
     overview: "Overview",
+    dashboardPageSubtitle: "Your search at a glance — response rate, funnel, and what needs attention.",
+    jobsPageSubtitle: "Filter, search, and manage every application in one table.",
+    kanbanPageSubtitle: "Drag a card between stages to update its status.",
+    remindersPageSubtitle: "Everything due for follow-up, soonest first.",
+    correspondencePageSubtitle: "Every message linked to a job, in one inbox.",
+    gmailReviewPageSubtitle: "Review Gmail threads before linking them to a job.",
     account: "Account",
     profile: "Profile",
     admin: "Admin",
@@ -981,6 +987,12 @@ export const translations = {
     home: "Hjem",
     analytics: "Analyse",
     overview: "Oversikt",
+    dashboardPageSubtitle: "Søket ditt i korte trekk — svarrate, trakt og hva som trenger oppmerksomhet.",
+    jobsPageSubtitle: "Filtrer, søk og administrer alle søknader i én tabell.",
+    kanbanPageSubtitle: "Dra et kort mellom stadier for å oppdatere status.",
+    remindersPageSubtitle: "Alt som trenger oppfølging, snarest først.",
+    correspondencePageSubtitle: "Alle meldinger koblet til en jobb, i én innboks.",
+    gmailReviewPageSubtitle: "Se gjennom Gmail-tråder før du kobler dem til en jobb.",
     account: "Konto",
     profile: "Profil",
     admin: "Admin",