fix(web): consolidate inline currency formatters into shared lib (GOO-205)

Remove 8 inline formatPrice/formatVND/formatPriceM2 functions scattered
across components and pages, replacing them with imports from
@/lib/currency. Add formatVNDFull (full locale, no compact notation) for
chuyen-nhuong pages. Fix price-history-chart off-by-1000 bug caused by
double-dividing through priceToMillions then formatMillions. Add k/m²
branch to formatPricePerM2 for sub-million values.

Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>

apps/web/components/chuyen-nhuong/chuyen-nhuong-detail-client.tsx

@@ -19,14 +19,12 @@ import {
   STATUS_LABELS,
 } from '@/lib/chuyen-nhuong-api';
 import { cn } from '@/lib/utils';
+import { formatVNDFull } from '@/lib/currency';
 
 interface ChuyenNhuongDetailClientProps {
   listing: TransferListingDetail;
 }
 
-function formatVND(value: string): string {
-  return new Intl.NumberFormat('vi-VN').format(Number(value)) + ' \u20ab';
-}
 
 export function ChuyenNhuongDetailClient({ listing }: ChuyenNhuongDetailClientProps) {
   const statusColor =
@@ -69,13 +67,13 @@ export function ChuyenNhuongDetailClient({ listing }: ChuyenNhuongDetailClientPr
       <div className="my-6 grid grid-cols-2 gap-4 rounded-lg border bg-card p-4 sm:grid-cols-4 lg:grid-cols-6">
         <QuickStat
           label="Giá yêu cầu"
-          value={formatVND(listing.askingPriceVND)}
+          value={formatVNDFull(listing.askingPriceVND)}
           valueClassName="text-primary"
         />
         {listing.aiEstimatePriceVND && (
           <QuickStat
             label="Giá AI ước tính"
-            value={formatVND(listing.aiEstimatePriceVND)}
+            value={formatVNDFull(listing.aiEstimatePriceVND)}
           />
         )}
         {listing.areaM2 && (
@@ -144,7 +142,7 @@ export function ChuyenNhuongDetailClient({ listing }: ChuyenNhuongDetailClientPr
                 {listing.monthlyRentVND && (
                   <div className="flex items-center justify-between">
                     <span className="text-sm text-muted-foreground">Tiền thuê hàng tháng</span>
-                    <span className="font-medium">{formatVND(listing.monthlyRentVND)}</span>
+                    <span className="font-medium">{formatVNDFull(listing.monthlyRentVND)}</span>
                   </div>
                 )}
                 {listing.depositMonths != null && (
@@ -181,14 +179,14 @@ export function ChuyenNhuongDetailClient({ listing }: ChuyenNhuongDetailClientPr
               <div className="flex items-center justify-between">
                 <span className="text-sm text-muted-foreground">Giá yêu cầu</span>
                 <span className="text-lg font-bold text-primary">
-                  {formatVND(listing.askingPriceVND)}
+                  {formatVNDFull(listing.askingPriceVND)}
                 </span>
               </div>
               {listing.aiEstimatePriceVND && (
                 <div className="flex items-center justify-between">
                   <span className="text-sm text-muted-foreground">Giá AI ước tính</span>
                   <span className="font-semibold">
-                    {formatVND(listing.aiEstimatePriceVND)}
+                    {formatVNDFull(listing.aiEstimatePriceVND)}
                   </span>
                 </div>
               )}

apps/web/components/chuyen-nhuong/transfer-item-table.tsx

@@ -7,14 +7,12 @@ import {
   CONDITION_COLORS,
   CONDITION_LABELS,
 } from '@/lib/chuyen-nhuong-api';
+import { formatVNDFull } from '@/lib/currency';
 
 interface TransferItemTableProps {
   items: TransferItemData[];
 }
 
-function formatVND(value: string): string {
-  return new Intl.NumberFormat('vi-VN').format(Number(value)) + ' \u20ab';
-}
 
 export function TransferItemTable({ items }: TransferItemTableProps) {
   if (items.length === 0) {
@@ -59,12 +57,12 @@ export function TransferItemTable({ items }: TransferItemTableProps) {
               </td>
               <td className="px-3 py-2 text-right">{item.quantity}</td>
               <td className="px-3 py-2 text-right font-medium">
-                {formatVND(item.askingPriceVND)}
+                {formatVNDFull(item.askingPriceVND)}
               </td>
               <td className="px-3 py-2 text-right text-muted-foreground">
                 {item.aiEstimatePriceVND ? (
                   <span title={item.aiConfidence ? `Độ tin cậy: ${Math.round(item.aiConfidence * 100)}%` : undefined}>
-                    {formatVND(item.aiEstimatePriceVND)}
+                    {formatVNDFull(item.aiEstimatePriceVND)}
                   </span>
                 ) : '—'}
               </td>

apps/web/components/chuyen-nhuong/transfer-listing-card.tsx

@@ -10,14 +10,12 @@ import {
   CATEGORY_LABELS,
   STATUS_LABELS,
 } from '@/lib/chuyen-nhuong-api';
+import { formatVNDFull } from '@/lib/currency';
 
 interface TransferListingCardProps {
   listing: TransferListingListItem;
 }
 
-function formatVND(value: string): string {
-  return new Intl.NumberFormat('vi-VN').format(Number(value)) + ' \u20ab';
-}
 
 export function TransferListingCard({ listing }: TransferListingCardProps) {
   const statusColor =
@@ -62,7 +60,7 @@ export function TransferListingCard({ listing }: TransferListingCardProps) {
           {/* Price */}
           <div className="mb-3">
             <p className="text-lg font-bold text-primary">
-              {formatVND(listing.askingPriceVND)}
+              {formatVNDFull(listing.askingPriceVND)}
             </p>
             {listing.isNegotiable && (
               <span className="text-xs text-muted-foreground">Thương lượng</span>