Connect Flutter phone auth and Android platform

public/api/v1/auth/request-otp.php

@@ -37,6 +37,7 @@ try {
     $db = Database::getInstance();
     $connection = $db->getConnection();
     $connection->begin_transaction();
+    $transactionOpen = true;
 
     $rateBuckets = [
         ['phone', hash_hmac('sha256', 'phone:' . $phone, $hashKey), 5, 3600],
@@ -57,6 +58,7 @@ try {
         $check->close();
         if ($count > $limit) {
             $connection->rollback();
+            $transactionOpen = false;
             api_json(['error' => 'rate_limited'], 429);
         }
     }
@@ -70,11 +72,12 @@ try {
     $insert->execute();
     $insert->close();
     $connection->commit();
+    $transactionOpen = false;
 
     (new ConfiguredHttpOtpProvider())->send($phone, $code);
     api_json(['challenge_id' => $challengeUuid, 'expires_in_seconds' => 300]);
 } catch (Throwable $exception) {
-    if (isset($connection) && $connection instanceof mysqli && $connection->errno === 0) {
+    if (!empty($transactionOpen) && isset($connection) && $connection instanceof mysqli) {
         try { $connection->rollback(); } catch (Throwable $ignored) {}
     }
     error_log('OTP request failed: ' . $exception->getMessage());