AddrSearch - Persian address -> coordinates

  GET  /health
  GET  /datasets
  GET  /search?q=<address>&limit=5&db=<dataset>
  POST /search           {"q":"...","limit":5,"db":"<dataset>"}
  GET  /searchAi?q=<address>&db=<dataset>   -> {"found":true,"lat":..,"lon":..,"score_percent":..}
  POST /searchAi         {"q":"...","db":"<dataset>"}
  POST /search/batch     {"queries":["..."],"limit":1,"db":"<dataset>"}

datasets: base, full, perfect
default : base   (used when 'db' is omitted)