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/analytics/presentation/dto/get-price-movers.dto.ts

@@ -0,0 +1,47 @@
+import { ApiProperty, ApiPropertyOptional } from '@nestjs/swagger';
+import { Type } from 'class-transformer';
+import { IsIn, IsInt, IsOptional, Max, Min } from 'class-validator';
+
+export class GetPriceMoversDto {
+  @ApiProperty({
+    description: 'Price movement direction',
+    enum: ['up', 'down'],
+    example: 'up',
+  })
+  @IsIn(['up', 'down'])
+  direction: 'up' | 'down' = 'up';
+
+  @ApiPropertyOptional({
+    description: 'Look-back period',
+    enum: ['7d', '14d', '30d'],
+    default: '7d',
+    example: '7d',
+  })
+  @IsOptional()
+  @IsIn(['7d', '14d', '30d'])
+  period: string = '7d';
+
+  @ApiPropertyOptional({
+    description: 'Maximum number of results to return',
+    minimum: 1,
+    maximum: 20,
+    default: 5,
+    example: 5,
+  })
+  @IsOptional()
+  @Type(() => Number)
+  @IsInt()
+  @Min(1)
+  @Max(20)
+  limit: number = 5;
+
+  @ApiPropertyOptional({
+    description: 'Geographic aggregation level (currently only "district" is supported)',
+    enum: ['district'],
+    default: 'district',
+    example: 'district',
+  })
+  @IsOptional()
+  @IsIn(['district'])
+  level: 'district' = 'district';
+}