codify "platform" into resolution logic, server-fn/fullstack overhaul (#4596)

overhaul dioxus fullstack using a new implementation of server_fn

This PR is a complete rewrite of dioxus fullstack designed to improve compatibility with axum and to fix a number of compilation errors based on feature flag unification plumbing through macros.

packages/core/src/any_props.rs

@@ -85,7 +85,7 @@ impl<F: ComponentFunction<P, M> + Clone, P: Clone + 'static, M: 'static> AnyProp
                     {
                         tracing::error!("Panic while rendering component `{_name}`: {err:?}");
                     }
-                    Element::Err(CapturedPanic { error: err }.into())
+                    Element::Err(CapturedPanic(err).into())
                 }
             }
         }