fix(school): show Nursery only for nursery classes, and say Girls' school

GIAS NurseryProvision is text ("Has Nursery Classes", "No Nursery
Classes", "Not applicable"), but the header and the place table tested it
for truthiness. Every school with a value got a Nursery chip or a "Yes",
including secondaries aged 11-18. hasNurseryClasses() matches the one
value that means a nursery, and the type now says the field is a string.

The single-sex chip appended 's to the plural GIAS gender, giving
"Girls's school". singleSexLabel() gives "Girls' school" / "Boys' school".

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

nextjs-app/__tests__/components/PlaceView.test.tsx

@@ -361,12 +361,12 @@ describe('PlaceView school attributes', () => {
       { urn: 1, school_name: 'Alpha Primary', phase: 'Primary',
         rwm_expected_pct: 82, attainment_8_score: null,
         age_range: '4-11', religious_denomination: 'Church of England',
-        nursery_provision: true,
+        nursery_provision: 'Has Nursery Classes',
         parliamentary_constituency: 'Chelmsford' } as never,
       { urn: 2, school_name: 'Beta High', phase: 'Secondary',
         rwm_expected_pct: null, attainment_8_score: 47,
         age_range: '11-16', religious_denomination: 'Does not apply',
-        nursery_provision: false,
+        nursery_provision: 'No Nursery Classes',
         parliamentary_constituency: 'Witham' } as never,
     ],
     averages: { rwm_expected_pct: 63, attainment_8_score: 45 },
@@ -459,6 +459,18 @@ describe('PlaceView school attributes', () => {
     expect(cells.slice(2)).toEqual(['—', '—', '—', '—']);
   });
 
+  it('reads "Not applicable" as no nursery, not as a yes', () => {
+    // GIAS sends text. Tested for truthiness, every value was a "Yes".
+    const notApplicable: PlaceDetail = {
+      ...withAttributes,
+      schools: [{ urn: 5, school_name: 'Epsilon Primary', phase: 'Primary',
+                  rwm_expected_pct: 70, nursery_provision: 'Not applicable' } as never],
+    };
+    const { container } = render(<PlaceView detail={notApplicable} phase="primary"
+      englandAverage={61} neighbours={[]} />);
+    expect(container.querySelector('tbody')!.textContent).not.toContain('Yes');
+  });
+
   it('gives an all-through school its nursery under primary only', () => {
     // All-through schools render in both groups. Nursery belongs to the
     // primary reading of the same school, not the secondary one.
@@ -467,7 +479,7 @@ describe('PlaceView school attributes', () => {
       schools: [{ urn: 4, school_name: 'Delta Academy', phase: 'All-through',
                   rwm_expected_pct: 66, attainment_8_score: 51,
                   age_range: '4-18', religious_denomination: 'None',
-                  nursery_provision: true,
+                  nursery_provision: 'Has Nursery Classes',
                   parliamentary_constituency: 'Chelmsford' } as never],
     };
     const { container } = render(<PlaceView detail={allThrough}