Enhance health check logic to allow partial database failures without throwing an error, improving resilience in environments with multiple databases.

app/controllers/api/health.php

@@ -136,7 +136,9 @@ App::get('/v1/health/db')
             }
         }
 
-        if (!empty($failures)) {
+        // Only throw error if ALL databases failed (no successful pings)
+        // This allows partial failures in environments where not all DBs are ready
+        if (!empty($failures) && empty($output)) {
             throw new Exception(Exception::GENERAL_SERVER_ERROR, 'DB failure on: ' . implode(", ", $failures));
         }