feat(inbox): show the hunt working, not just spinning (#1526)

A pass runs for over two minutes and reports nothing until it lands. The
only sign of life was a spinner inside a button and a number that did not
move, so the honest reading was that nothing was happening.

A band under the header now names the mailboxes actually being read, keeps
a running count of omgång and hämtade as passes land, and offers Avbryt
without hunting for it in Settings.

The bar is deliberately indeterminate. There is no honest percentage
inside a pass, and inventing one to look finished is worse than admitting
the wait. Reduced motion holds the sweep still and dims it instead of
removing it, because the band still has to read as active.

The result line waits for the run to end rather than sitting under a live
one, so a press replaces itself in place.

Co-authored-by: Jakob Wennberg <311770904+jakobwennberg-oss@users.noreply.github.com>
Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

app/globals.css

@@ -704,3 +704,23 @@ input[type="number"] {
     opacity: 1;
   }
 }
+
+/* Indeterminate sweep for the receipt hunt.
+   A pass runs for over two minutes and reports nothing until it lands, so
+   there is no honest percentage to show inside one. This says "still working"
+   without inventing progress. Reduced motion holds it still and dims it
+   rather than removing it: the band still has to read as active. */
+@keyframes hunt-sweep {
+  0% { transform: translateX(-100%); }
+  100% { transform: translateX(400%); }
+}
+.hunt-sweep {
+  animation: hunt-sweep 1.6s ease-in-out infinite;
+}
+@media (prefers-reduced-motion: reduce) {
+  .hunt-sweep {
+    animation: none;
+    width: 100%;
+    opacity: 0.35;
+  }
+}