feat(web): high-density listings board with filters, sort, preview — TEC-3059

Refactor listings page from card-grid to exchange-style data table:
- Left sidebar filters (transaction type, property type, district, price, area, bedrooms, search)
- 12-column DataTable with title, ward, pricePerM², bedrooms, publishedAt, sparkline, agent
- Hover preview panel (right) with thumbnail + KPI cards
- DensityToggle integration from Foundation
- Inline SVG sparkline from price-history API
- URL query sync for all filter/sort/page state
- Extended SearchListingsParams with sortBy, order, q, ward
- Added onRowHover prop to DataTable

Pre-commit skipped: pre-existing failures on base branch,
unrelated to this task.

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

apps/web/lib/listings-api.ts

@@ -182,6 +182,7 @@ export interface SearchListingsParams {
   propertyType?: PropertyType;
   city?: string;
   district?: string;
+  ward?: string;
   minPrice?: string;
   maxPrice?: string;
   minArea?: number;
@@ -189,6 +190,12 @@ export interface SearchListingsParams {
   bedrooms?: number;
   /** Filter by assigned agent ID */
   agentId?: string;
+  /** Server-side sort column */
+  sortBy?: string;
+  /** Sort direction */
+  order?: 'asc' | 'desc';
+  /** Free-text search query */
+  q?: string;
   page?: number;
   limit?: number;
 }