fix(federation): address code review findings for FED-009

- Resolve homeUserId from DB in sendFederatedCallStart/End (not raw userId)
- Clear existing timeout in createFederatedCall before overwriting
- Clear federatedCallToken/Url in leaveVoice and handleForceDisconnect
- Remove unnecessary `as any` cast in relay processor

packages/server/src/routes/federation.ts

@@ -3092,7 +3092,7 @@ function processDmCallStartEvent(
       callerName: callerStub.displayName ?? callerStub.username,
       livekitUrl: event.call!.livekitUrl,
       livekitToken: token,
-    } as any);
+    });
   }
 
   accepted.push(event.messageId);