[Bug] Proxy ordered route selector should skip malformed orderTopicConf entries

### Bug description

`MessageQueueSelector.buildWrite` parses ordered topic route data from `TopicRouteWrapper.getOrderTopicConf()` as `brokerName:queueNum` entries separated by `;`.

The current implementation assumes every entry has both parts and that `queueNum` is numeric:

```java
String[] item = broker.split(":");
String brokerName = item[0];
int nums = Integer.parseInt(item[1]);
```

If the route data contains a malformed entry such as `broker-a`, `broker-a:not-a-number`, or an empty broker name, queue selector construction can throw `ArrayIndexOutOfBoundsException` or `NumberFormatException`. This makes one bad ordered-route fragment break the whole proxy write queue selection path.

### Expected behavior

The proxy should tolerate malformed ordered-route fragments. Invalid fragments should be skipped with a diagnostic warning, while valid fragments in the same `orderTopicConf` should still be used to build write queues.

### Affected area

`proxy` module, route selection for ordered topic write queues.

### Suggested fix

- Validate each `orderTopicConf` fragment before parsing.
- Skip entries with missing broker name, missing queue count, or non-numeric queue count.
- Keep existing behavior for valid `brokerName:queueNum` entries.
- Add unit tests for mixed valid and invalid ordered-route fragments.

Start in the proxy module at MessageQueueSelector.buildWrite and inspect how TopicRouteWrapper.getOrderTopicConf() fragments are parsed. Add unit tests covering mixed valid and malformed brokerName:queueNum entries, then verify that valid fragments still build write queues while invalid ones produce warnings and do not throw.

Written by the indexing model from the issue text.