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.

examples/01-app-demos/dog_app.rs

@@ -0,0 +1,70 @@
+//! This example demonstrates a simple app that fetches a list of dog breeds and displays a random dog.
+//!
+//! This app combines `use_loader` and `use_action` to fetch data from the Dog API.
+//! - `use_loader` automatically fetches the list of dog breeds when the component mounts.
+//! - `use_action` fetches a random dog image whenever the `.dispatch` method is called.
+
+use dioxus::prelude::*;
+use serde::{Deserialize, Serialize};
+use std::collections::HashMap;
+
+fn main() {
+    dioxus::launch(app);
+}
+
+fn app() -> Element {
+    // Fetch the list of breeds from the Dog API, using the `?` syntax to suspend or throw errors
+    let breed_list = use_loader(move || async move {
+        #[derive(Deserialize, Serialize, Debug, PartialEq, Clone)]
+        struct ListBreeds {
+            message: HashMap<String, Vec<String>>,
+        }
+
+        reqwest::get("https://dog.ceo/api/breeds/list/all")
+            .await?
+            .json::<ListBreeds>()
+            .await
+    })?;
+
+    // Whenever this action is called, it will re-run the future and return the result.
+    let mut breed = use_action(move |breed| async move {
+        #[derive(Deserialize, Serialize, Debug, PartialEq)]
+        struct DogApi {
+            message: String,
+        }
+
+        reqwest::get(format!("https://dog.ceo/api/breed/{breed}/images/random"))
+            .await
+            .unwrap()
+            .json::<DogApi>()
+            .await
+    });
+
+    rsx! {
+        h1 { "Doggo selector" }
+        div { width: "400px",
+            for cur_breed in breed_list.read().message.keys().take(20).cloned() {
+                button {
+                    onclick: move |_| {
+                        breed.call(cur_breed.clone());
+                    },
+                    "{cur_breed}"
+                }
+            }
+        }
+        div {
+            match breed.result() {
+                None => rsx! { div { "Click the button to fetch a dog!" } },
+                Some(Err(_e)) => rsx! { div { "Failed to fetch a dog, please try again." } },
+                Some(Ok(res)) => rsx! {
+                    img {
+                        max_width: "500px",
+                        max_height: "500px",
+                        src: "{res.read().message}"
+                    }
+                },
+            }
+        }
+
+    }
+}