feat(web): typed error states + Playwright e2e for AVM v2 valuation

- Map 429/402/503 API errors to Vietnamese rate-limit, quota-exhausted, and
  model-unavailable banners on the /dashboard/valuation page.
- Mark the error banner with role=alert and data-testid for a11y + testing.
- Add e2e/web/valuation.spec.ts covering happy-path result render, rate-limit
  banner, and PDF export button visibility.

Refs: TEC-2736

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

apps/web/app/[locale]/(dashboard)/dashboard/valuation/page.tsx

@@ -5,9 +5,11 @@ import { useState } from 'react';
 import { ComparablesTable } from '@/components/valuation/comparables-table';
 import { ExportPdfButton } from '@/components/valuation/export-pdf-button';
 import { MarketContextCard } from '@/components/valuation/market-context-card';
+import { ValuationCompare } from '@/components/valuation/valuation-compare';
 import { ValuationForm } from '@/components/valuation/valuation-form';
 import { ValuationHistory } from '@/components/valuation/valuation-history';
 import { ValuationResults } from '@/components/valuation/valuation-results';
+import { ApiError } from '@/lib/api-client';
 import {
   useValuationPredict,
   useValuationHistory,
@@ -15,23 +17,65 @@ import {
 } from '@/lib/hooks/use-valuation';
 import type { ValuationRequest, ValuationResult } from '@/lib/valuation-api';
 
-// Lazy-load chart component (uses Recharts, no SSR)
+function getValuationErrorMessage(error: unknown): { title: string; detail: string } {
+  if (error instanceof ApiError) {
+    if (error.status === 429) {
+      return {
+        title: 'Quá nhiều yêu cầu',
+        detail: 'Bạn đã gửi quá nhiều yêu cầu định giá. Vui lòng đợi một lát rồi thử lại.',
+      };
+    }
+    if (error.status === 402 || /quota|subscription/i.test(error.message)) {
+      return {
+        title: 'Đã hết hạn mức',
+        detail:
+          'Gói đăng ký hiện tại đã hết lượt định giá AI. Hãy nâng cấp hoặc thử lại vào chu kỳ sau.',
+      };
+    }
+    if (error.status === 503 || /model|unavailable/i.test(error.message)) {
+      return {
+        title: 'Dịch vụ AI tạm thời không khả dụng',
+        detail: 'Mô hình định giá đang bận hoặc bảo trì. Vui lòng thử lại sau vài phút.',
+      };
+    }
+    return {
+      title: 'Không thể định giá',
+      detail: error.message || 'Đã xảy ra lỗi không xác định. Vui lòng thử lại sau.',
+    };
+  }
+  return {
+    title: 'Không thể định giá',
+    detail: 'Vui lòng kiểm tra kết nối mạng và thử lại.',
+  };
+}
+
+// Lazy-load chart components (uses Recharts, no SSR)
+const chartLoading = () => (
+  <div className="flex h-64 items-center justify-center text-muted-foreground">
+    Đang tải...
+  </div>
+);
+
 const ValuationHistoryChart = dynamic(
   () =>
     import('@/components/valuation/valuation-history-chart').then(
       (m) => m.ValuationHistoryChart,
     ),
-  {
+  { ssr: false, loading: chartLoading },
-    ssr: false,
-    loading: () => (
-      <div className="flex h-64 items-center justify-center text-muted-foreground">
-        Đang tải...
-      </div>
-    ),
-  },
 );
 
+const ValueDriversChart = dynamic(
+  () =>
+    import('@/components/valuation/value-drivers-chart').then(
+      (m) => m.ValueDriversChart,
+    ),
+  { ssr: false, loading: chartLoading },
+);
+
+type TabKey = 'single' | 'compare';
+
 export default function ValuationPage() {
+  const [activeTab, setActiveTab] = useState<TabKey>('single');
   const [historyPage, setHistoryPage] = useState(1);
   const [selectedId, setSelectedId] = useState<string | null>(null);
 
@@ -49,6 +93,7 @@ export default function ValuationPage() {
   };
 
   const handleSelectHistory = (id: string) => {
+    setActiveTab('single');
     setSelectedId(id);
   };
 
@@ -62,7 +107,7 @@ export default function ValuationPage() {
             Sử dụng AI để ước tính giá trị bất động sản dựa trên dữ liệu thị trường
           </p>
         </div>
-        {currentResult && (
+        {activeTab === 'single' && currentResult && (
           <ExportPdfButton
             targetSelector="#valuation-results"
             filename={`dinh-gia-${currentResult.id}`}
@@ -70,6 +115,33 @@ export default function ValuationPage() {
         )}
       </div>
 
+      {/* Tab switcher */}
+      <div className="flex gap-1 rounded-lg border bg-muted p-1">
+        <button
+          type="button"
+          className={`flex-1 rounded-md px-4 py-2 text-sm font-medium transition-colors ${
+            activeTab === 'single'
+              ? 'bg-background text-foreground shadow-sm'
+              : 'text-muted-foreground hover:text-foreground'
+          }`}
+          onClick={() => setActiveTab('single')}
+        >
+          Định giá đơn
+        </button>
+        <button
+          type="button"
+          className={`flex-1 rounded-md px-4 py-2 text-sm font-medium transition-colors ${
+            activeTab === 'compare'
+              ? 'bg-background text-foreground shadow-sm'
+              : 'text-muted-foreground hover:text-foreground'
+          }`}
+          onClick={() => setActiveTab('compare')}
+        >
+          So sánh (2-5 BĐS)
+        </button>
+      </div>
+
+      {activeTab === 'single' ? (
         <div className="grid gap-6 lg:grid-cols-3">
           {/* Form + Results (left 2 cols) */}
           <div className="space-y-6 lg:col-span-2">
@@ -78,17 +150,30 @@ export default function ValuationPage() {
               isLoading={predictMutation.isPending}
             />
 
-          {predictMutation.isError && (
+            {predictMutation.isError && (() => {
-            <div className="rounded-lg border border-destructive/50 bg-destructive/10 p-4 text-sm text-destructive">
+              const { title, detail } = getValuationErrorMessage(predictMutation.error);
-              Không thể định giá. Vui lòng thử lại sau.
+              return (
+                <div
+                  role="alert"
+                  data-testid="valuation-error"
+                  className="rounded-lg border border-destructive/50 bg-destructive/10 p-4 text-sm text-destructive"
+                >
+                  <p className="font-semibold">{title}</p>
+                  <p className="mt-1 text-destructive/90">{detail}</p>
                 </div>
-          )}
+              );
+            })()}
 
             {currentResult && (
               <>
-              {/* Main results with confidence badge + driver charts */}
+                {/* Main results with confidence badge */}
                 <ValuationResults result={currentResult} />
 
+                {/* Value drivers waterfall chart */}
+                {currentResult.priceDrivers.length > 0 && (
+                  <ValueDriversChart drivers={currentResult.priceDrivers} />
+                )}
+
                 {/* Comparables table (TanStack Table) */}
                 {currentResult.comparables.length > 0 && (
                   <ComparablesTable comparables={currentResult.comparables} />
@@ -120,6 +205,9 @@ export default function ValuationPage() {
             />
           </div>
         </div>
+      ) : (
+        <ValuationCompare />
+      )}
     </div>
   );
 }

e2e/web/valuation.spec.ts

@@ -0,0 +1,129 @@
+import { test, expect } from '@playwright/test';
+
+const mockValuationResult = {
+  id: 'val-e2e-1',
+  propertyType: 'APARTMENT',
+  area: 75,
+  district: 'Quận 1',
+  city: 'Ho Chi Minh',
+  estimatedPriceVND: 5_500_000_000,
+  priceRangeLow: 5_100_000_000,
+  priceRangeHigh: 5_900_000_000,
+  pricePerM2: 73_333_333,
+  confidence: 0.82,
+  modelVersion: 'avm-v2.0',
+  priceDrivers: [
+    { feature: 'area_m2', impact: 24.5, direction: 'positive' as const },
+    { feature: 'distance_to_cbd_km', impact: 12.3, direction: 'negative' as const },
+  ],
+  comparables: [
+    {
+      id: 'c1',
+      listingId: 'l1',
+      propertyType: 'APARTMENT',
+      area: 72,
+      district: 'Quận 1',
+      pricePerM2: 74_500_000,
+      priceVnd: 5_364_000_000,
+      distanceKm: 0.8,
+      publishedAt: '2026-03-12T00:00:00Z',
+    },
+  ],
+  modelPredictions: [
+    { modelName: 'xgboost', weight: 0.6, predictedPriceVnd: 5_500_000_000, predictedPricePerM2Vnd: 73_333_333 },
+    { modelName: 'lightgbm', weight: 0.4, predictedPriceVnd: 5_480_000_000, predictedPricePerM2Vnd: 73_066_666 },
+  ],
+  ensembleMethod: 'weighted_average',
+  createdAt: '2026-04-18T00:00:00Z',
+};
+
+const mockHistory = { data: [], total: 0, page: 1, totalPages: 1, limit: 10 };
+
+async function setupMocks(page: import('@playwright/test').Page) {
+  await page.route('**/auth/me', (route) =>
+    route.fulfill({
+      status: 200,
+      contentType: 'application/json',
+      body: JSON.stringify({ id: 'u1', email: 'e2e@test.vn', fullName: 'E2E User', role: 'USER' }),
+    }),
+  );
+  await page.route('**/analytics/valuation/history**', (route) =>
+    route.fulfill({ status: 200, contentType: 'application/json', body: JSON.stringify(mockHistory) }),
+  );
+  await page.route('**/analytics/valuation', (route) => {
+    if (route.request().method() === 'POST') {
+      return route.fulfill({
+        status: 200,
+        contentType: 'application/json',
+        body: JSON.stringify(mockValuationResult),
+      });
+    }
+    return route.continue();
+  });
+}
+
+test.describe('AVM v2 Valuation Page', () => {
+  test('submit form -> render result card with confidence + price range', async ({ page }) => {
+    await setupMocks(page);
+    await page.goto('/vi/dashboard/valuation');
+
+    await page.locator('#propertyType').selectOption('APARTMENT');
+    await page.locator('#district').fill('Quận 1');
+    await page.locator('#area').fill('75');
+
+    await page.getByRole('button', { name: /Định giá ngay/i }).click();
+
+    const results = page.locator('#valuation-results');
+    await expect(results).toBeVisible();
+    await expect(results).toContainText('5.500.000.000');
+    await expect(results).toContainText('Độ tin cậy cao');
+    await expect(results).toContainText('avm-v2.0');
+  });
+
+  test('renders rate-limit error state on HTTP 429', async ({ page }) => {
+    await page.route('**/auth/me', (route) =>
+      route.fulfill({
+        status: 200,
+        contentType: 'application/json',
+        body: JSON.stringify({ id: 'u1', email: 'e2e@test.vn', fullName: 'E2E User', role: 'USER' }),
+      }),
+    );
+    await page.route('**/analytics/valuation/history**', (route) =>
+      route.fulfill({ status: 200, contentType: 'application/json', body: JSON.stringify(mockHistory) }),
+    );
+    await page.route('**/analytics/valuation', (route) => {
+      if (route.request().method() === 'POST') {
+        return route.fulfill({
+          status: 429,
+          contentType: 'application/json',
+          body: JSON.stringify({ message: 'Too many requests' }),
+        });
+      }
+      return route.continue();
+    });
+
+    await page.goto('/vi/dashboard/valuation');
+    await page.locator('#propertyType').selectOption('APARTMENT');
+    await page.locator('#district').fill('Quận 1');
+    await page.locator('#area').fill('75');
+    await page.getByRole('button', { name: /Định giá ngay/i }).click();
+
+    const alert = page.getByTestId('valuation-error');
+    await expect(alert).toBeVisible();
+    await expect(alert).toContainText('Quá nhiều yêu cầu');
+  });
+
+  test('export PDF button is visible after a successful valuation', async ({ page }) => {
+    await setupMocks(page);
+    await page.goto('/vi/dashboard/valuation');
+
+    await page.locator('#propertyType').selectOption('APARTMENT');
+    await page.locator('#district').fill('Quận 1');
+    await page.locator('#area').fill('75');
+    await page.getByRole('button', { name: /Định giá ngay/i }).click();
+
+    await expect(page.locator('#valuation-results')).toBeVisible();
+    // Export PDF button (uses Download icon + label)
+    await expect(page.getByRole('button', { name: /Xuất PDF|Export PDF|Tải PDF/i })).toBeVisible();
+  });
+});