Better expect error messages (#2629)

* Replace expect error messages

* Change message

* Create RuntimeError struct

* Pass error through core methods

* Fix use of Runtime::current in signals package

* Fix tests

* Add #[track_caller] for better error output and fix maybe_with_rt

* provide a help message along with RuntimeError

---------

Co-authored-by: Evan Almloff <evanalmloff@gmail.com>

packages/core/src/error_boundary.rs

@@ -167,7 +167,7 @@ where
                 error.context.push(Rc::new(AdditionalErrorContext {
                     backtrace: Backtrace::capture(),
                     context: Box::new(context()),
-                    scope: current_scope_id(),
+                    scope: current_scope_id().ok(),
                 }));
                 Err(error)
             }