fix: mount data/ read-write so mediagis import chown works

docker-compose.yml

@@ -23,7 +23,9 @@ services:
       IMPORT_US_POSTCODES: "true"
       THREADS: ${NOMINATIM_THREADS:-4}
     volumes:
-      - ./data:/nominatim/data:ro
+      # Must be read-write: mediagis init.sh chowns /nominatim/data during import.
+      # :ro aborts import → empty search results.
+      - ./data:/nominatim/data
       - nominatim-pgdata:/var/lib/postgresql/16/main
     shm_size: ${NOMINATIM_SHM_SIZE:-1gb}
     healthcheck: