feat(runtime): native platform backends and UI vessels onto main

ui/tools/native-codegen/test_app.el

@@ -0,0 +1,28 @@
+component App {
+  state {
+    counter: Int = 0
+    input_text: String = ""
+  }
+
+  fn increment(widget: Int, data: String) -> Void {
+    state.counter = state.counter + 1
+    widget_set_text(g_w_count_label, str_concat("Count: ", int_to_str(g_counter)))
+  }
+
+  fn on_name_change(widget: Int, data: String) -> Void {
+    state.input_text = data
+    widget_set_disabled(g_w_btn_greet, str_len(g_input_text) == 0)
+  }
+
+  template {
+    <vstack spacing=24 padding=20 bg="#0f172a">
+      <label text="Hello World" style="heading" />
+      <hstack spacing=8>
+        <text_field placeholder="Enter name" on_change=on_name_change flex=1 />
+        <button label="Greet" on_click=on_greet_click disabled={str_len(state.input_text) == 0} />
+      </hstack>
+      <label text="Count: {state.counter}" />
+      <button label="Increment" on_click=increment />
+    </vstack>
+  }
+}