very elegant extension API and parts of it used in std as POC

orchid-std/src/main.rs

@@ -0,0 +1,4 @@
+use orchid_extension::entrypoint::{extension_main, ExtensionData};
+use orchid_std::StdSystem;
+
+pub fn main() { extension_main(ExtensionData { systems: &[&StdSystem] }) }