feat: 优化 IndexController 中的距离计算逻辑，提高代码可读性和性能

app/api/controller/IndexController.php

@@ -135,9 +135,8 @@ class IndexController extends BaseApiController
             $latitude = $params['lat'];
             $longitude = $params['long'];
             // 计算距离的SQL表达式
-            $distanceSql = "SQRT(POW(69.1 * (latitude - {$latitude}), 2) +
-                POW(69.1 * ({$longitude} - longitude) * COS(latitude / 57.3), 2))";
-            $find = SystemStore::field("id, name,abbreviation, {$distanceSql} AS distance")
+            $distanceExpr = "6371 * 2 * ASIN(SQRT(POWER(SIN(({$latitude} - abs(latitude)) * pi()/180 / 2), 2) + COS({$latitude} * pi()/180) * COS(abs(latitude) * pi()/180) * POWER(SIN(({$longitude} - longitude) * pi()/180 / 2), 2)))";
+            $find = SystemStore::field("id, name,abbreviation, {$distanceExpr} AS distance")
                 ->where('is_show', '=', 1)
                 ->where('latitude', '<>', '')
                 ->where('longitude', '<>', '')