Add AllowAnonymous to QBittorrent health check endpoints

This fix allows Cleanuparr to successfully connect to RDT Client by making the
health check endpoints accessible without authentication, matching real qBittorrent
behavior. The three endpoints affected are:
- /api/v2/app/version
- /api/v2/app/webapiVersion
- /api/v2/app/buildInfo

Fixes #867

server/RdtClient.Web/Controllers/QBittorrentController.cs

@@ -62,6 +62,7 @@ public class QBittorrentController(ILogger<QBittorrentController> logger, QBitto
         return Ok();
     }
 
+    [AllowAnonymous]
     [Route("app/version")]
     [HttpGet]
     [HttpPost]
@@ -70,6 +71,7 @@ public class QBittorrentController(ILogger<QBittorrentController> logger, QBitto
         return Ok("v4.3.2");
     }
 
+    [AllowAnonymous]
     [Route("app/webapiVersion")]
     [HttpGet]
     [HttpPost]
@@ -78,6 +80,7 @@ public class QBittorrentController(ILogger<QBittorrentController> logger, QBitto
         return Ok("2.7");
     }
 
+    [AllowAnonymous]
     [Route("app/buildInfo")]
     [HttpGet]
     [HttpPost]