copy(web): replace em dashes in public copy

Rewrites every visitor-facing string that used an em dash, choosing the
punctuation for what the dash was doing: a colon before a list or
explanation, a comma for an aside, a full stop between two thoughts,
parentheses for an aside mid-sentence. Covers page titles and meta
descriptions, the home and admissions guide copy, school page headings
and notes, the compare page, metric labels and tooltips.

Two rewrites also fix the sentence around them: the closure banner no
longer repeats "proposed for closure", and the cut-off caveat's list of
priorities now parses.

A lone dash marking a missing value in a table cell stays: it is a data
convention, not prose. A Jest guard walks the source with the TypeScript
parser and fails on any other em dash in a string or JSX text node.

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

nextjs-app/components/compare/CompareAdmissions.tsx

@@ -49,17 +49,17 @@ export function CompareAdmissions({
       how={
         <>
           From the most recent admissions round ({entryLabel}). &quot;First choice&quot; means
-          families who ranked the school top of their application form — officially a &quot;first
-          preference&quot;. Schools never see your ranking: places are decided only by the
+          families who ranked the school top of their application form (officially a &quot;first
+          preference&quot;). Schools never see your ranking: places are decided only by the
           school&apos;s admission criteria, so listing a school lower down never hurts your chances.
-          These are National Offer Day offers — waiting lists and appeals can change the final
+          These are National Offer Day offers. Waiting lists and appeals can change the final
           intake.
         </>
       }
     >
       <SectionGrid schools={schools}>
         <Measure
-          tip="How many application forms named the school at any preference rank — not the number of families competing head-to-head for a place."
+          tip="How many application forms named the school at any preference rank. This is not the number of families competing head-to-head for a place."
           label="Interest in the school"
         >
         {schools.map((school, i) => {
@@ -126,7 +126,7 @@ export function CompareAdmissions({
               // Selective schools: the entrance test decides, whatever the
               // offer percentage looks like — never the distance template.
               text =
-                'Entry is by entrance test — the school is selective; distance and preference rank don’t decide places.';
+                'Entry is by entrance test. The school is selective, so distance and preference rank don’t decide places.';
             } else if (summary.firstPrefPct >= 100) {
               text = `Every family who put ${school.school_name} first got a place.`;
             } else if (summary.firstPrefPct >= 90) {
@@ -134,9 +134,9 @@ export function CompareAdmissions({
             } else if (a?.oversubscribed) {
               text = isSecondary
                 ? faith
-                  ? 'More first-choice applications than places — check the school’s admission criteria (faith-based criteria may apply).'
-                  : 'More first-choice applications than places — check the school’s admission criteria (catchment or distance often decides, but criteria vary).'
-                : 'More first-choice applications than places — check the school’s admission criteria (for most non-faith primaries, distance decides).';
+                  ? 'More first-choice applications than places. Check the school’s admission criteria (faith-based criteria may apply).'
+                  : 'More first-choice applications than places. Check the school’s admission criteria (catchment or distance often decides, but criteria vary).'
+                : 'More first-choice applications than places. Check the school’s admission criteria (for most non-faith primaries, distance decides).';
             } else {
               text = `${summary.firstPrefPct}% of first-choice families received an offer.`;
             }