feat(ext/setup): wizard Style C progress track, glyph mode icons, recovery QR banner

- Replace dot-based progress indicator with colored horizontal segment track
  (completed=green, active=gold, pending=border) via renderProgressTrack()
- Add SETUP_STEP_NAMES constant for track segment titles
- Update Step 0 mode cards with glyph icons (◈ create, ⌥ attach)
- Add recovery QR banner in Step 5 (new-vault only, verifiedHandle present)
  with Generate now / Skip buttons wired in attachStep5()
- Add CSS for .setup-progress-track, .setup-progress-segment variants,
  and .recovery-qr-banner to styles.css

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

extension/src/popup/styles.css

@@ -424,6 +424,41 @@ textarea {
   background: #aa812a;
 }
 
+/* Setup wizard — Style C progress track */
+.setup-progress-track {
+  display: flex;
+  gap: 4px;
+  width: 100%;
+  max-width: 560px;
+  margin: 8px auto 16px;
+}
+.setup-progress-segment {
+  flex: 1;
+  height: 4px;
+  border-radius: 2px;
+}
+.setup-progress-segment--completed { background: var(--success, #238636); }
+.setup-progress-segment--active    { background: var(--gold, #b8860b); }
+.setup-progress-segment--pending   { background: var(--border, #30363d); }
+
+/* Setup wizard — Recovery QR banner */
+.recovery-qr-banner {
+  padding: 12px 16px;
+  background: var(--bg-elevated, #161b22);
+  border: 1px solid var(--gold, #b8860b);
+  border-radius: 8px;
+}
+.recovery-qr-banner__header {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  margin-bottom: 4px;
+}
+.recovery-qr-banner__actions {
+  display: flex;
+  gap: 8px;
+}
+
 /* Spinner */
 .spinner {
   display: inline-block;