fix(admissions): move the cut-off detail into its own section

The admissions card measured 1503px on a live school page — half the height
of every section put together, and nearly three times the next largest — with
its default view rendering as four tiles adrift in about 1080px of blank card.

The cause was a layout trick meeting content it was never sized for. The
admissions views are stacked in one grid cell so switching them never shifts
layout, and the hidden ones keep their box: only visibility is dropped. That
works while the views are comparable. The distance view added in #102 carries
a chart, a table and a map, came to 1402px against the tile grid's 316px, and
pinned every other view to its height — including the one that renders by
default, which nobody had clicked.

Rather than only unpinning it, the detail moves out. Every other topic on the
page is a section with a nav entry, and "how close did we need to live, and
would we have got in?" is a topic, not a variant reading of the intake
figures. The headline number stays on the Admissions tile where the intake
story is; the record behind it now lives in a Distance section directly below.

  admissions   1503px -> 554px
  distance        new -> 743px   (median section on the page is ~528px)

Three further changes, each of which also makes the content better rather
than only shorter:

  * The map renders on request. Before a postcode is entered it is a circle
    drawn round a school, and it costs a Leaflet bundle and 240px to say so;
    a successful check opens it automatically, which is the point at which it
    starts answering something. Map height 320px -> 240px.
  * The chart appears only at the four published years that let the summary
    state a direction. Below that we already refuse to call the series a
    trend, and a line through three points asserts one regardless of what the
    sentence beneath it admits. The table carries those years anyway, with
    the reasons a line cannot show.
  * Three caveat paragraphs become one. They said walking-route twice and
    made the same point about priorities in two voices. It now sits in
    CutoffDistanceDetail rather than inside the check, so it still renders
    for a school with coordinates missing, where there is a table but no map
    and no check.

The new e2e guard asserts no section exceeds 2.5x the median section height.
Measuring the card's internals cannot catch this: the tile grid is flex: 1,
so it absorbs the stretch and every box still looks full. The first version
of this test targeted an arbitrary primary, passed against the live bug, and
proved nothing; pointed at a school that actually holds cut-off history it
fails on staging with "#admissions is 1459px against a 526px median".

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WDvkyqqHABm4bmth2kjAxE

nextjs-app/components/school/lastDistanceOffered.ts

@@ -294,31 +294,31 @@ export function compareToCutoffs(
 }
 
 /**
- * The limits of the check, stated where a parent will act on it.
+ * The limits of the figure, and of the check made against it.
  *
- * Every clause is load-bearing. Distance is the last criterion applied, not the
- * first; the authority's own measurement may be a walking route rather than a
- * straight line, which is always longer for the same home; and a past cut-off
- * constrains next year's not at all.
+ * One caveat, rendered once at the end of the section. It was previously three
+ * paragraphs — under the map, under the check, and a trailing "not a catchment"
+ * line — which took ~180px between them, said walking-route twice, and made
+ * the same point about priorities in two voices.
+ *
+ * Phrased to stand up whether or not the postcode check is on the page: it
+ * opens on the figure rather than on "your result", because a school with no
+ * coordinates renders the table with no check beneath it.
+ *
+ * Every claim is still here:
+ *   * distance is the last criterion applied, not the first;
+ *   * the figures and rings are straight-line, and not a boundary;
+ *   * some authorities measure a walking route, always longer for the same home;
+ *   * a past cut-off constrains next year's not at all.
  */
 export const CUTOFF_CHECK_CAVEAT =
-  'An indication only. Places go first to children in care, EHCP places, '
-  + 'siblings and — at faith schools — on faith criteria, so a home inside the '
-  + 'distance can still miss out. Some authorities measure a walking route '
-  + 'rather than a straight line, which is always longer for the same home, and '
-  + "next year's cut-off depends on next year's applicants. Always check the "
-  + "school's own admissions policy.";
-
-/**
- * The rings are a drawing of a number, not a boundary anyone administers.
- *
- * The walking-route caveat belongs to CUTOFF_CHECK_CAVEAT immediately below
- * this on the page, which states it more usefully ("always longer for the same
- * home"). Saying it in both places read as a stutter.
- */
-export const CUTOFF_MAP_CAVEAT =
-  'Each ring is the straight-line cut-off for that year, drawn around the '
-  + 'school. It illustrates the distance — it is not a catchment boundary.';
+  'Distance is the last criterion applied. Places go first to children in care, '
+  + 'EHCP places, siblings and — at faith schools — on faith criteria, so a home '
+  + 'inside the distance can still miss out. Figures are straight-line distances '
+  + 'and not a catchment boundary; some authorities measure a walking route '
+  + "instead, which is always longer for the same home. Next year's cut-off "
+  + "depends on next year's applicants — always check the school's own "
+  + 'admissions policy.';
 
 // ---------------------------------------------------------------------------
 // When there is no figure
@@ -375,3 +375,16 @@ export function cutoffCoverageNote(rows: CutoffYearRow[]): string | null {
   return `Only ${published} ${published === 1 ? 'year has' : 'years have'} a published figure, `
     + 'which is too few to read as a trend.';
 }
+
+/**
+ * Whether there is enough of a record to justify a section of its own.
+ *
+ * Two published years is the floor: one is a fact the Admissions tile already
+ * states, and a chart of a single point invites a trend reading that is not
+ * there. Shared so the section, its nav entry and the detail component cannot
+ * disagree about when it exists — a nav link to a section that did not render
+ * is exactly the failure this codebase keeps warning about.
+ */
+export function hasCutoffDetail(rows: CutoffYearRow[]): boolean {
+  return rows.filter((r) => r.status === 'published').length >= 2;
+}