fix(picloudserver): use piMin<ssize_t> to avoid signed/unsigned UB in Client::readDevice

piMini(max_size, buff.size()) implicitly narrows size_t to int,
which is UB for large buffers. Replace with explicit piMin<ssize_t>
matching the correct pattern used in picloudclient.cpp.

libs/cloud/picloudserver.cpp

@@ -201,7 +201,7 @@ ssize_t PICloudServer::Client::readDevice(void * read_to, ssize_t max_size) {
 		if (buff.isEmpty()) {
 			sz = 0;
 		} else {
-			sz = piMini(max_size, buff.size());
+			sz = piMin<ssize_t>(max_size, buff.size_s());
 			memcpy(read_to, buff.data(), sz);
 			buff.remove(0, sz);
 		}