feat(osm): Phase 6 — proximity materialized views + refresh cron

* `mv_park_nearest_poi` — for each IndustrialPark, the 3 nearest POI of
  six priority categories (HOSPITAL/BANK/GAS/BUS/METRO/POLICE) within
  5km. Refreshed weekly. Pre-aggregated 6,513 rows from the live
  catalog so the KCN sidebar can render in <50ms instead of running
  ST_Distance for every page hit.
* `mv_poi_density_by_province` — count of POI per (province, category)
  for analytics heatmaps.
* `OsmSyncService.refreshMaterializedViews()` calls
  `REFRESH MATERIALIZED VIEW CONCURRENTLY` so reads aren't blocked.
* New cron entry `weeklyRefreshViews` (Sun 04:00 ICT) and admin
  endpoint `POST /admin/osm/refresh-views` for on-demand refresh.

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

apps/api/src/modules/osm-sync/infrastructure/osm-sync.service.ts

@@ -78,6 +78,22 @@ export class OsmSyncService {
     private readonly logger: LoggerService,
   ) {}
 
+  /**
+   * Refresh the proximity / density materialized views. Called by the
+   * cron and from the admin "Refresh views" button. Runs concurrently
+   * (`CONCURRENTLY`) so reads aren't blocked.
+   */
+  async refreshMaterializedViews(): Promise<void> {
+    this.logger.log('Refreshing materialized views', 'OsmSyncService');
+    await this.prisma.$executeRawUnsafe(
+      `REFRESH MATERIALIZED VIEW CONCURRENTLY "mv_park_nearest_poi"`,
+    );
+    await this.prisma.$executeRawUnsafe(
+      `REFRESH MATERIALIZED VIEW "mv_poi_density_by_province"`,
+    );
+    this.logger.log('Materialized views refreshed', 'OsmSyncService');
+  }
+
   /** Look up a sync layer by its (layer, category) tuple. */
   findLayer(layer: string, category?: string | null): OsmSyncLayerDef | undefined {
     return SYNC_LAYERS.find(