Add process collector

src/main.cpp

@@ -1,10 +1,10 @@
 #include "config.hpp"
 #include "connection.hpp"
-#include "connection_handler.hpp"
 #include "http_handler.hpp"
+#include "metric.hpp"
 #include "perfetto_categories.hpp"
+#include "process_collector.hpp"
 #include "server.hpp"
-#include <atomic>
 #include <csignal>
 #include <cstring>
 #include <fcntl.h>
@@ -176,6 +176,9 @@ int main(int argc, char *argv[]) {
   perfetto::TrackEvent::Register();
 #endif
 
+  // Register the process collector for default metrics.
+  metric::register_collector(std::make_shared<ProcessCollector>());
+
   std::string config_file = "config.toml";
 
   // Parse command line arguments