feat: add unit tests for featured listings, neighborhood scores + price history chart

- Add unit tests for FeatureListingHandler (6 tests) and ActivateFeaturedListingHandler (6 tests)
- Add unit tests for NeighborhoodScoreServiceImpl (5 tests) and GetNeighborhoodScoreHandler (2 tests)
- Add PriceHistoryChart component with recharts LineChart for listing detail page
- Wire up price history API client and integrate chart into listing detail view

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/api/src/modules/analytics/infrastructure/__tests__/neighborhood-score.service.spec.ts

@@ -0,0 +1,132 @@
+import { NeighborhoodScoreServiceImpl } from '../services/neighborhood-score.service';
+
+describe('NeighborhoodScoreServiceImpl', () => {
+  let service: NeighborhoodScoreServiceImpl;
+  let mockPrisma: {
+    neighborhoodScore: { findUnique: ReturnType<typeof vi.fn>; upsert: ReturnType<typeof vi.fn> };
+    pOI: { count: ReturnType<typeof vi.fn> };
+  };
+  let mockLogger: { log: ReturnType<typeof vi.fn> };
+
+  beforeEach(() => {
+    mockPrisma = {
+      neighborhoodScore: {
+        findUnique: vi.fn(),
+        upsert: vi.fn(),
+      },
+      pOI: { count: vi.fn() },
+    };
+    mockLogger = { log: vi.fn() };
+
+    service = new NeighborhoodScoreServiceImpl(mockPrisma as any, mockLogger as any);
+  });
+
+  describe('getScore', () => {
+    it('returns existing score from database', async () => {
+      const stored = {
+        district: 'Quận 1',
+        city: 'Hồ Chí Minh',
+        educationScore: 8,
+        healthcareScore: 7,
+        transportScore: 9,
+        shoppingScore: 6,
+        greeneryScore: 5,
+        safetyScore: 4,
+        totalScore: 68.5,
+        poiCounts: { education: 12, healthcare: 5 },
+        calculatedAt: new Date(),
+      };
+      mockPrisma.neighborhoodScore.findUnique.mockResolvedValue(stored);
+
+      const result = await service.getScore('Quận 1', 'Hồ Chí Minh');
+
+      expect(result).not.toBeNull();
+      expect(result!.district).toBe('Quận 1');
+      expect(result!.totalScore).toBe(68.5);
+      expect(result!.poiCounts).toEqual({ education: 12, healthcare: 5 });
+    });
+
+    it('returns null when no score exists', async () => {
+      mockPrisma.neighborhoodScore.findUnique.mockResolvedValue(null);
+
+      const result = await service.getScore('Quận 99', 'Hồ Chí Minh');
+
+      expect(result).toBeNull();
+    });
+  });
+
+  describe('calculateAndSave', () => {
+    it('calculates scores from POI counts and upserts', async () => {
+      // Simulate POI counts: education=15 (max), healthcare=4 (50%), transport=6 (50%),
+      // shopping=5 (50%), greenery=3 (50%), safety=2 (50%)
+      const poiCountsByCategory = [15, 4, 6, 5, 3, 2];
+      let callIndex = 0;
+      mockPrisma.pOI.count.mockImplementation(() => {
+        return Promise.resolve(poiCountsByCategory[callIndex++]!);
+      });
+
+      mockPrisma.neighborhoodScore.upsert.mockImplementation(({ create }) => {
+        return Promise.resolve(create);
+      });
+
+      const result = await service.calculateAndSave('Quận 1', 'Hồ Chí Minh');
+
+      // education: 15/15 * 10 = 10 → 10 * 20/10 = 20
+      // healthcare: 4/8 * 10 = 5 → 5 * 20/10 = 10
+      // transport: 6/12 * 10 = 5 → 5 * 20/10 = 10
+      // shopping: 5/10 * 10 = 5 → 5 * 15/10 = 7.5
+      // greenery: 3/6 * 10 = 5 → 5 * 15/10 = 7.5
+      // safety: 2/4 * 10 = 5 → 5 * 10/10 = 5
+      // total = 20 + 10 + 10 + 7.5 + 7.5 + 5 = 60
+      expect(result.educationScore).toBe(10);
+      expect(result.healthcareScore).toBe(5);
+      expect(result.totalScore).toBe(60);
+      expect(mockPrisma.neighborhoodScore.upsert).toHaveBeenCalledTimes(1);
+    });
+
+    it('caps category scores at 10', async () => {
+      // All categories have way more POIs than max
+      mockPrisma.pOI.count.mockResolvedValue(100);
+      mockPrisma.neighborhoodScore.upsert.mockImplementation(({ create }) => {
+        return Promise.resolve(create);
+      });
+
+      const result = await service.calculateAndSave('Quận 1', 'Hồ Chí Minh');
+
+      // All scores capped at 10 → total = sum of weights = 100
+      expect(result.educationScore).toBe(10);
+      expect(result.healthcareScore).toBe(10);
+      expect(result.transportScore).toBe(10);
+      expect(result.shoppingScore).toBe(10);
+      expect(result.greeneryScore).toBe(10);
+      expect(result.safetyScore).toBe(10);
+      expect(result.totalScore).toBe(100);
+    });
+
+    it('returns 0 scores when no POIs exist', async () => {
+      mockPrisma.pOI.count.mockResolvedValue(0);
+      mockPrisma.neighborhoodScore.upsert.mockImplementation(({ create }) => {
+        return Promise.resolve(create);
+      });
+
+      const result = await service.calculateAndSave('Quận 1', 'Hồ Chí Minh');
+
+      expect(result.educationScore).toBe(0);
+      expect(result.totalScore).toBe(0);
+    });
+
+    it('logs the calculated score', async () => {
+      mockPrisma.pOI.count.mockResolvedValue(5);
+      mockPrisma.neighborhoodScore.upsert.mockImplementation(({ create }) => {
+        return Promise.resolve(create);
+      });
+
+      await service.calculateAndSave('Quận 1', 'Hồ Chí Minh');
+
+      expect(mockLogger.log).toHaveBeenCalledWith(
+        expect.stringContaining('Quận 1'),
+        'NeighborhoodScoreService',
+      );
+    });
+  });
+});