feat: implement home winners selection logic with fallback handling and add integration tests

tests/int/home-winner-selection.int.spec.ts

@@ -0,0 +1,32 @@
+import { describe, expect, it } from 'vitest'
+
+import type { CmsRouteDoc } from '@/spa/cmsRoute'
+import { resolveHomeWinners } from '@/spa/homeWinnerSelection'
+
+const selected2026Winners: CmsRouteDoc[] = Array.from({ length: 16 }, (_, index) => ({
+  id: 65 + index,
+  title: `Winner ${65 + index}`,
+  year: 2026,
+}))
+
+const published2025Winners: CmsRouteDoc[] = Array.from({ length: 9 }, (_, index) => ({
+  id: 12 + index,
+  title: `Winner ${12 + index}`,
+  year: 2025,
+}))
+
+describe('home winner selection', () => {
+  it('uses a non-empty CMS selection without appending winners from the fallback year', () => {
+    const featured = selected2026Winners.map(({ id }) => id)
+    const winners = resolveHomeWinners(featured, [...selected2026Winners, ...published2025Winners], [])
+
+    expect(winners).toEqual(selected2026Winners)
+    expect(winners.some((winner) => winner.year === 2025)).toBe(false)
+  })
+
+  it('falls back to at most eight 2025 winners when the CMS selection is empty', () => {
+    const winners = resolveHomeWinners([], published2025Winners, [])
+
+    expect(winners).toEqual(published2025Winners.slice(0, 8))
+  })
+})