feat(api): keep page helper out of prelude

Keep the beginner prelude focused on generated authoring primitives by leaving page-boundary rendering as an explicit helper instead of a glob-import default.

req: dx/006

req: public_api/005

hemx-test/tests/examples_contract.rs

@@ -151,6 +151,7 @@ fn public_prelude_does_not_export_low_level_primitives() {
         "GeneratedTarget",
         "Handle",
         "ParamName",
+        "page",
     ] {
         assert!(
             !exported.contains(&token),

hemx/src/lib.rs

@@ -176,7 +176,7 @@ where
 }
 
 pub mod prelude {
-    pub use crate::{page, Html};
+    pub use crate::Html;
     pub use hemx_core::{
         navigate, push, redirect, replace, CssClass, CssClasses, Form, FormModel, FormValue,
         IntoEffect,
@@ -214,7 +214,7 @@ mod tests {
         // req: dx/006 req: public_api/005 req: html_safety/002
         use crate::prelude::*;
 
-        let html = Html::join([page(&InlineView)]);
+        let html = Html::join([crate::page(&InlineView)]);
 
         assert_eq!(html.as_str(), "<strong>ok</strong>");
     }