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/components/JobDetailsDialog.tsx

@@ -1231,13 +1231,14 @@ function MatchScoreCard({ score, loading }: { score: MatchScore | null; loading:
     <Box sx={{ p: 1.75, mb: 2, borderRadius: 3, border: "1px solid", borderColor: "divider", backgroundColor: "background.default" }}>
       <Box sx={{ display: "flex", gap: 2.5, alignItems: "center", flexWrap: "wrap", mb: 1.5 }}>
         {score.hasEnoughSignal ? (
-          <Box sx={{ position: "relative", width: 92, height: 92, flexShrink: 0 }}>
-            <CircularProgress variant="determinate" value={100} size={92} thickness={4} sx={{ color: "divider", position: "absolute" }} />
+          <Box role="img" aria-label={`${t("matchScoreTitle")}: ${score.score}%`} sx={{ position: "relative", width: 92, height: 92, flexShrink: 0 }}>
+            <CircularProgress variant="determinate" value={100} size={92} thickness={4} aria-hidden="true" sx={{ color: "divider", position: "absolute" }} />
             <CircularProgress
               variant="determinate"
               value={score.score}
               size={92}
               thickness={4}
+              aria-hidden="true"
               color={color === "inherit" ? "primary" : color}
               sx={{ position: "absolute", "& .MuiCircularProgress-circle": { strokeLinecap: "round" } }}
             />