plugin: log dylib load + service init/poll to debug missing singleton registration

plugin/src/lib.rs

@@ -1,3 +1,10 @@
 pub mod cpu_service;
 pub mod stats;
 pub mod system_stats;
+
+// Fires when the .so is dlopen'd. Tells us the plugin file actually loaded,
+// independent of whether qml_register_types runs.
+#[ctor::ctor(unsafe)]
+fn on_dylib_load() {
+    eprintln!("[nova-plugin] dylib loaded (libNovaStats.so)");
+}