update the dioxus cratesio readme, add many more examples (#5501)

* update the dioxus cratesio readme

* fix example

* fix header

* add a bunch more examples

examples/04-managing-state/read_signal.rs

@@ -0,0 +1,37 @@
+//! Passing a read-only signal to a child component.
+//!
+//! `ReadSignal<T>` is a signal that can only be read, not written. Taking it as a prop is
+//! the idiomatic way to tell a child "you can subscribe to this value, but you can't change
+//! it." Any `Signal<T>` or `Memo<T>` coerces into a `ReadSignal<T>` automatically, so the
+//! parent passes them in unchanged.
+
+use dioxus::prelude::*;
+
+fn main() {
+    dioxus::launch(app);
+}
+
+fn app() -> Element {
+    let mut count = use_signal(|| 0);
+    let doubled = use_memo(move || count() * 2);
+
+    rsx! {
+        h1 { "Parent" }
+        button { onclick: move |_| count += 1, "Increment" }
+
+        // Both Signal and Memo implement Into<ReadSignal<T>>
+        Display { label: "Count", value: count }
+        Display { label: "Doubled", value: doubled }
+
+        // You can also pass a plain value — it'll be wrapped automatically
+        Display { label: "Constant", value: 42 }
+    }
+}
+
+// Taking `ReadSignal<i32>` means the child can subscribe but can't mutate the source
+#[component]
+fn Display(label: String, value: ReadSignal<i32>) -> Element {
+    rsx! {
+        p { "{label}: {value}" }
+    }
+}