feat(web): add Property Valuation UI with AVM integration

Build the valuation page at /dashboard/valuation with form input,
AI-powered price estimation results, comparable properties display,
and valuation history. Add "Dinh gia AI" button to listing detail
sidebar for quick per-listing estimates.

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

apps/web/lib/valuation-api.ts

@@ -0,0 +1,85 @@
+import { apiClient } from './api-client';
+
+// ─── Types ──────────────────────────────────────────────
+
+export interface ValuationRequest {
+  propertyType: string;
+  area: number;
+  district: string;
+  city: string;
+  bedrooms?: number;
+  bathrooms?: number;
+  floors?: number;
+  frontage?: number;
+  roadWidth?: number;
+  yearBuilt?: number;
+  hasLegalPaper?: boolean;
+}
+
+export interface ValuationComparable {
+  id: string;
+  title: string;
+  address: string;
+  district: string;
+  priceVND: string;
+  areaM2: number;
+  pricePerM2: number;
+  similarity: number;
+  latitude?: number;
+  longitude?: number;
+}
+
+export interface PriceDriver {
+  feature: string;
+  impact: number;
+  direction: 'positive' | 'negative';
+}
+
+export interface ValuationResult {
+  id: string;
+  estimatedPriceVND: number;
+  confidence: number;
+  pricePerM2: number;
+  priceRangeLow: number;
+  priceRangeHigh: number;
+  comparables: ValuationComparable[];
+  priceDrivers: PriceDriver[];
+  modelVersion: string;
+  createdAt: string;
+}
+
+export interface ValuationHistoryItem {
+  id: string;
+  propertyType: string;
+  district: string;
+  city: string;
+  area: number;
+  estimatedPriceVND: number;
+  confidence: number;
+  createdAt: string;
+}
+
+export interface ValuationHistoryResponse {
+  data: ValuationHistoryItem[];
+  total: number;
+  page: number;
+  limit: number;
+}
+
+// ─── API ────────────────────────────────────────────────
+
+export const valuationApi = {
+  predict: (data: ValuationRequest) =>
+    apiClient.post<ValuationResult>('/valuation/predict', data),
+
+  getHistory: (page = 1, limit = 10) =>
+    apiClient.get<ValuationHistoryResponse>(
+      `/valuation/history?page=${page}&limit=${limit}`,
+    ),
+
+  getById: (id: string) =>
+    apiClient.get<ValuationResult>(`/valuation/${id}`),
+
+  predictForListing: (listingId: string) =>
+    apiClient.post<ValuationResult>(`/valuation/predict-listing/${listingId}`),
+};