feat(errors): add stable error propagation

firmware/libs/kaptan-err-propagate-macros/tests/ui/union.rs

@@ -0,0 +1,8 @@
+use kaptan_err_propagate_macros::KaptanError;
+
+#[derive(KaptanError)]
+union NotAnError {
+    code: u8,
+}
+
+fn main() {}