feat(11-03): cpvDivisions column — normalizer + backfill migration

Adds Tender.cpvDivisions String[] (@@index Gin) derived at ingestion time
via cpv-catalog.ts's divisionOf() — replaces exact-match cpvCodes
comparison with a typesafe, GIN-indexable hasSome target (FILTER-03,
Pitfall 2). Backfill migration 20260721150000_tender_cpv_divisions_backfill
applied locally: 1612/1671 rows populated across all observed divisions
(741 rows carry division '45' — Bauarbeiten); idempotent (second run:
UPDATE 0, ADD COLUMN IF NOT EXISTS / CREATE INDEX IF NOT EXISTS both skip
cleanly). Applied via docker exec psql + `prisma migrate resolve
--applied` + `prisma generate` against the local dev DB only — no
Docker deploy on the test server.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/api/src/tenders/tender-normalizer.service.spec.ts

@@ -120,6 +120,42 @@ describe('TenderNormalizerService', () => {
     expect(normalized.bundesland).toBeNull();
   });
 
+  it('derives distinct cpvDivisions (leading 2 digits) from cpvCodes (FILTER-03, Pitfall 2)', () => {
+    const raw = loadRawNoticePair(NOTICE_WITH_EFORMS_ONLY_DEADLINE);
+
+    const normalized = service.normalize(raw);
+
+    expect(Array.isArray(normalized.cpvDivisions)).toBe(true);
+    for (const division of normalized.cpvDivisions) {
+      expect(division).toMatch(/^\d{2}$/);
+    }
+    // Every cpvCodes entry must normalize into one of the derived divisions.
+    for (const code of normalized.cpvCodes) {
+      const digits = code.replace(/\D/g, '');
+      if (digits.length >= 2) {
+        expect(normalized.cpvDivisions).toContain(digits.slice(0, 2));
+      }
+    }
+  });
+
+  it('cpvDivisions is an empty array when cpvCodes is empty — never crashes', () => {
+    const raw = loadRawNoticePair(NOTICE_WITH_NO_DEADLINE_OR_VALUE);
+    const rawWithoutCpv: RawTenderRecord = {
+      ...raw,
+      ocdsPayload: {
+        ...(raw.ocdsPayload as Record<string, unknown>),
+        tender: {
+          ...(raw.ocdsPayload as { tender?: Record<string, unknown> })?.tender,
+          items: [],
+        },
+      },
+    };
+
+    const normalized = service.normalize(rawWithoutCpv);
+
+    expect(normalized.cpvDivisions).toEqual([]);
+  });
+
   it('dedupKey = ocid when present', () => {
     const raw = loadRawNoticePair(NOTICE_WITH_EFORMS_ONLY_DEADLINE);