maven: fix test mocks for CalendarEvents interface (verification)

- Add CalendarEvents method to recordingAPI in auth_test.go
- Add CalendarEvents method to fakeCore in handlers_test.go

Co-Authored-By: opencode <opencode@anthropic.com>

internal/voice/server.go

@@ -234,4 +234,4 @@ func marshalResult(v any) json.RawMessage {
 	return b
 }
 
-// io.EOF — used by serveConn to detect a quiet client disconnect.
+// io.EOF — used by serveConn to detect a quiet client disconnect.