fix(school): send the school page its admissions policy, and read it exactly

The header's Selective flag read school_info.admissions_policy, which the
detail endpoint never sent, so no school page could flag Selective while
its search row did (staging E2E: The Grammar School at Leeds). The detail
payload now carries it, and a contract test checks it carries every field
the header's flags read.

Sending it would have switched on two older copies of the tag logic #176
fixed in the rows. The Admissions section and the cut-off note both tested
includes('selective'), so every non-selective secondary would have read
"entry is by selective examination". The section also counted "None" as a
faith: Burntwood reads "a faith-based admissions priority (None)" today.
All of them now share isSelective() and hasReligiousCharacter(), which also
treats "Not applicable" as no faith, as the place table already does.

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

nextjs-app/lib/utils.ts

@@ -923,12 +923,22 @@ export function isSpecialSchool(school: { school_type?: string | null }): boolea
 }
 
 /**
- * Whether GIAS records a religious character. "None" and "Does not apply" are
- * the register's two ways of saying it has none, and neither is a faith.
+ * Whether GIAS records a religious character. "None", "Does not apply" and
+ * "Not applicable" are the register's ways of saying it has none; the place
+ * table (PlaceView's NO_FAITH) reads the same three.
  */
 export function hasReligiousCharacter(value: string | null | undefined): boolean {
   const v = value?.trim().toLowerCase() ?? '';
-  return v !== '' && v !== 'none' && v !== 'does not apply';
+  return v !== '' && v !== 'none' && v !== 'does not apply' && v !== 'not applicable';
+}
+
+/**
+ * Whether GIAS records the school as selective. Exact: "Non-selective"
+ * contains "selective", so a substring test read every comprehensive as
+ * selective. (The register files a partly selective school as non-selective.)
+ */
+export function isSelective(admissionsPolicy: string | null | undefined): boolean {
+  return admissionsPolicy?.trim().toLowerCase() === 'selective';
 }
 
 /**