debug: add logging for order update messages

Add detailed logging to orders channel handler to track:
- When order update messages are received from WebSocket
- Individual order update events being processed

This will help diagnose whether fill information is embedded
in order status updates rather than delivered via fills channel.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

apps/runner/src/index.ts

@@ -834,8 +834,10 @@ function handlePrivateMessage(
   if (channel.startsWith("orders.") && channel.endsWith(address)) {
     const payload = parsed.data;
     const records = Array.isArray(payload) ? payload : [payload];
+    logger.info({ accountId, channel, recordCount: records.length }, 'Received order update message from WebSocket');
     for (const record of records) {
       const update = record ?? {};
+      logger.info({ accountId, orderUpdate: update }, 'Processing order update event');
       routeOrder(accountId, update);
     }
     return;