feat(listings): phase C — nearby POIs on listing detail map

Backend
-------
- New endpoint GET /analytics/pois/nearby?lat&lng&radius&limit (public,
  no guard). Mirrors the neighborhoods/:district/score shape.
- Prisma $queryRawUnsafe with PostGIS ST_DWithin on POI.location::geography
  and ST_Distance for the ordered-by-distance result. Default radius 2km,
  max 10km; default limit 30, max 100.
- Response maps POIType enum → frontend POICategory so the existing pill
  filter in NeighborhoodPOIMap works out of the box:
    SCHOOL/UNIVERSITY → school
    HOSPITAL/CLINIC/PHARMACY → hospital
    METRO_STATION/BUS_STOP → transit
    MALL/MARKET/SUPERMARKET/BANK/ATM → shopping
    RESTAURANT/CAFE → restaurant
    PARK → park
    else → shopping (fallback, still filterable)
- New files: application/queries/get-nearby-pois/{query,handler}.ts +
  presentation/dto/get-nearby-pois.dto.ts. Registered in analytics.module.ts.

Frontend
--------
- analytics-api.ts: exports NearbyPOI, NearbyPOIsResponse, NearbyPOICategory
  and analyticsApi.getNearbyPOIs(lat, lng, radius?, limit?).
- listing-detail-client.tsx: the "Vị trí trên bản đồ" card no longer
  renders <ListingMap> for a single pin — it now renders
  <NeighborhoodPOIMap> with the property's coords as center, the nearby
  POIs as markers, and the existing category-filter pills. A small
  "Tìm thấy N điểm quan tâm trong bán kính 2 km" summary sits below.
- The neighborhood score radar card remains below, untouched.
- The spec fixture + mocks extended for the new analyticsApi dependency.

No schema change, no migration. Phase C of 4.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/api/src/modules/analytics/presentation/dto/get-nearby-pois.dto.ts

@@ -0,0 +1,35 @@
+import { ApiProperty } from '@nestjs/swagger';
+import { Transform } from 'class-transformer';
+import { IsNumber, IsOptional, Max, Min } from 'class-validator';
+
+export class GetNearbyPOIsDto {
+  @ApiProperty({ description: 'Latitude (-90..90)', example: 10.7975 })
+  @Transform(({ value }) => Number(value))
+  @IsNumber()
+  @Min(-90)
+  @Max(90)
+  lat!: number;
+
+  @ApiProperty({ description: 'Longitude (-180..180)', example: 106.721 })
+  @Transform(({ value }) => Number(value))
+  @IsNumber()
+  @Min(-180)
+  @Max(180)
+  lng!: number;
+
+  @ApiProperty({ description: 'Search radius in meters', default: 2000, required: false })
+  @IsOptional()
+  @Transform(({ value }) => (value === undefined ? undefined : Number(value)))
+  @IsNumber()
+  @Min(1)
+  @Max(10_000)
+  radius?: number;
+
+  @ApiProperty({ description: 'Maximum POIs to return', default: 30, required: false })
+  @IsOptional()
+  @Transform(({ value }) => (value === undefined ? undefined : Number(value)))
+  @IsNumber()
+  @Min(1)
+  @Max(100)
+  limit?: number;
+}