fix(search): address review on the shared result rows

- The rows' narrow layout now switches at a 608px list, not 600px. Below
  769px the page pads 1rem each side, so a 640px screen gives a 608px
  list: exactly the old max-width: 640px media query, where 600px left
  633-640px screens on the wide layout.
- rowContainerGuard.test.ts fails if anything other than HomeView renders
  SchoolRow or SecondarySchoolRow, or if one of HomeView's row lists loses
  its `results` container. Outside one the rows silently keep their wide
  layout on phones. (Checked: HomeView is the only importer today.)
- Picking a pin from the list beside the map now works from the keyboard:
  each row carries a "Show <school> on the map" button, visually hidden
  until focused, with aria-pressed for the selected school. The row itself
  cannot be the button, since it holds links and buttons of its own.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

nextjs-app/components/SecondarySchoolRow.module.css

@@ -235,12 +235,13 @@
 /*
  * Narrow: content full width, actions in a row beneath. Keyed to the list the
  * row sits in, not the screen, because the same row fills the phone list and
- * the ~400px list beside the map on desktop. HomeView makes both lists a
- * `results` container; outside one, the row keeps its wide layout.
- * 600px of list is a 632px screen less the page's padding, so phones behave
- * as they did under the old max-width: 640px media query.
+ * the ~430px list beside the map on desktop. HomeView makes its lists a
+ * `results` container; outside one, the row keeps its wide layout, which is
+ * why rowContainerGuard.test.ts fails if anything else renders this row.
+ * 608px is exact: below 769px the page pads 1rem each side, so a 640px screen
+ * gives a 608px list, matching the old max-width: 640px media query.
  */
-@container results (max-width: 600px) {
+@container results (max-width: 608px) {
   .row {
     flex-wrap: wrap;
     padding: 0.875rem;