feat(analytics): add GET /analytics/price-movers endpoint

Top tăng/giảm giá theo district cho Home dashboard.
Compares avg listing prices between current and previous time windows,
filters by min sample size (10), caches for 30 min.

TEC-3053

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

apps/api/src/modules/shared/infrastructure/cache.service.ts

@@ -37,6 +37,8 @@ export const CacheTTL = {
   MARKET_SNAPSHOT: 300, // 5 min
   /** Trending areas — 30 min TTL, aggregation is expensive */
   TRENDING_AREAS: 1800, // 30 min
+  /** Price movers — 30 min TTL, aggregation over two time windows */
+  PRICE_MOVERS: 1800, // 30 min
 } as const;
 
 export enum CachePrefix {
@@ -55,6 +57,7 @@ export enum CachePrefix {
   AGENT_LISTINGS = 'cache:agent:listings',
   MARKET_SNAPSHOT = 'cache:analytics:market_snapshot',
   TRENDING_AREAS = 'cache:analytics:trending_areas',
+  PRICE_MOVERS = 'cache:analytics:price_movers',
 }
 
 @Injectable()