refactor(web): dedup tỷ/triệu compact formatters (GOO-206)

- Add `formatCompact` as an exported alias for `formatPrice` in lib/currency.ts
- Replace 5 inline copies of the tỷ/triệu compact formatter:
  - components/map/listing-map.tsx (local `formatPrice` fn)
  - components/agents/agent-profile-client.tsx (local `fmtVND` fn)
  - app/(dashboard)/dashboard/saved-searches/page.tsx (local `formatPrice` fn)
  - app/(public)/page.tsx (local `formatVnd` fn + `vndFmt` Intl instance)
  - components/listings/price-history-chart.tsx (local `formatMillions` + `priceToMillions`)

All call sites now import from the canonical lib/currency module.
PriceHistoryChart now stores raw VND in chart data (was: millions) so
formatCompact emits correct tỷ/triệu labels using canonical thresholds.

Pre-existing test failures in inquiry/lead/AVM specs are unrelated to this change.

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

apps/web/components/agents/agent-profile-client.tsx

@@ -39,6 +39,7 @@ import { Button } from '@/components/ui/button';
 import { Card, CardContent, CardHeader, CardTitle, CardDescription } from '@/components/ui/card';
 import { Link } from '@/i18n/navigation';
 import type { AgentPublicProfile, AgentReviewItem } from '@/lib/agents-api';
+import { formatCompact } from '@/lib/currency';
 import { shimmerBlurDataURL } from '@/lib/image-blur';
 import type { ListingDetail } from '@/lib/listings-api';
 
@@ -48,12 +49,6 @@ import type { ListingDetail } from '@/lib/listings-api';
 
 const VND = new Intl.NumberFormat('vi-VN');
 
-function fmtVND(value: string | number | bigint): string {
-  const n = typeof value === 'bigint' ? Number(value) : Number(value);
-  if (n >= 1_000_000_000) return `${(n / 1_000_000_000).toFixed(1)} tỷ`;
-  if (n >= 1_000_000) return `${(n / 1_000_000).toFixed(0)} tr`;
-  return VND.format(n);
-}
 
 function qualityLabel(score: number): string {
   if (score >= 80) return 'Xuất sắc';
@@ -145,7 +140,7 @@ const listingColumns: DataTableColumn<ListingDetail>[] = [
     sortValue: (row) => Number(row.priceVND),
     cell: (row) => (
       <span className="text-xs font-semibold tabular-nums text-primary">
-        {fmtVND(row.priceVND)}
+        {formatCompact(row.priceVND)}
       </span>
     ),
     width: '12%',
@@ -160,7 +155,7 @@ const listingColumns: DataTableColumn<ListingDetail>[] = [
     cell: (row) =>
       row.pricePerM2 != null ? (
         <span className="text-xs tabular-nums text-foreground-muted">
-          {fmtVND(row.pricePerM2)}
+          {formatCompact(row.pricePerM2)}
         </span>
       ) : (
         <span className="text-xs text-foreground-dim">—</span>
@@ -384,7 +379,7 @@ export function AgentProfileClient({
         />
         <KpiCard
           label="Giá TB"
-          value={avgPriceVND != null ? fmtVND(avgPriceVND) : '—'}
+          value={avgPriceVND != null ? formatCompact(avgPriceVND) : '—'}
           icon={<BarChart2 className="h-4 w-4" />}
           footnote="Danh mục hiện tại"
         />

apps/web/components/listings/price-history-chart.tsx

@@ -11,21 +11,13 @@ import {
 } from 'recharts';
 
 import type { PriceHistoryItem } from '@/lib/listings-api';
+import { formatCompact } from '@/lib/currency';
 
 interface PriceHistoryChartProps {
   data: PriceHistoryItem[];
   height?: number;
 }
 
-function priceToMillions(priceStr: string): number {
-  return Math.round(Number(priceStr) / 1_000_000);
-}
-
-function formatMillions(value: number): string {
-  if (value >= 1000) return `${(value / 1000).toFixed(1)} tỷ`;
-  return `${value} tr`;
-}
-
 export function PriceHistoryChart({ data, height = 280 }: PriceHistoryChartProps) {
   if (data.length === 0) return null;
 
@@ -37,7 +29,7 @@ export function PriceHistoryChart({ data, height = 280 }: PriceHistoryChartProps
         month: '2-digit',
         year: 'numeric',
       }),
-      price: priceToMillions(item.newPrice),
+      price: Number(item.newPrice),
     }));
 
   return (
@@ -48,7 +40,7 @@ export function PriceHistoryChart({ data, height = 280 }: PriceHistoryChartProps
         <YAxis
           tick={{ fontSize: 11 }}
           className="fill-muted-foreground"
-          tickFormatter={(v: number) => formatMillions(v)}
+          tickFormatter={(v: number) => formatCompact(v)}
         />
         <Tooltip
           contentStyle={{
@@ -57,7 +49,7 @@ export function PriceHistoryChart({ data, height = 280 }: PriceHistoryChartProps
             borderRadius: '0.5rem',
             fontSize: '0.875rem',
           }}
-          formatter={(value) => [formatMillions(Number(value)), 'Giá']}
+          formatter={(value) => [formatCompact(Number(value)), 'Giá']}
         />
         <Line
           type="monotone"

apps/web/components/map/listing-map.tsx

@@ -5,16 +5,10 @@ import mapboxgl from 'mapbox-gl';
 import * as React from 'react';
 import 'mapbox-gl/dist/mapbox-gl.css';
 import { ComponentErrorBoundary } from '@/components/error-boundary';
+import { formatCompact } from '@/lib/currency';
 import type { ListingDetail } from '@/lib/listings-api';
 import { useMapboxStyle } from '@/lib/mapbox-style';
 
-function formatPrice(priceVND: string): string {
-  const num = Number(priceVND);
-  if (num >= 1_000_000_000) return `${(num / 1_000_000_000).toFixed(1)} tỷ`;
-  if (num >= 1_000_000) return `${(num / 1_000_000).toFixed(0)} tr`;
-  return num.toLocaleString('vi-VN');
-}
-
 interface ListingMapProps {
   listings: ListingDetail[];
   onMarkerClick?: (listing: ListingDetail) => void;
@@ -67,7 +61,7 @@ function buildGeoJSON(
       geometry: { type: 'Point', coordinates: [lng, lat] },
       properties: {
         id: listing.id,
-        price: formatPrice(listing.priceVND),
+        price: formatCompact(listing.priceVND),
         title: listing.property.title,
         district: listing.property.district ?? '',
         city: listing.property.city ?? '',
@@ -100,7 +94,7 @@ function buildPopupContent(listing: ListingDetail): HTMLDivElement {
   const price = document.createElement('p');
   price.style.cssText =
     'font-weight:700;color:hsl(var(--primary));font-size:14px;margin:0 0 4px;';
-  price.textContent = `${formatPrice(listing.priceVND)} VND`;
+  price.textContent = `${formatCompact(listing.priceVND)} VND`;
   container.appendChild(price);
 
   const title = document.createElement('p');