feat(build): make generated page helper canonical

Move canonical examples and docs snippets from raw render/page calls to generated ui::page helpers, hide generated render behind doc(hidden), and let form resources participate in generated target inspection for tests.

req: canonical_authoring/005

req: dx/006

req: codegen/002

req: public_api/002

req: test/001

examples/kanban/src/main.rs

@@ -281,15 +281,15 @@ fn parse_column(value: Option<&str>) -> usize {
 
 fn page_html(board: &BoardState) -> Html {
     // req: html_safety/002 req: view/001
-    board_ui::render(&Board {
+    board_ui::page(&Board {
         options: render_options(),
-        board: ui::render(&board_view(board)),
+        board: ui::page(&board_view(board)),
     })
 }
 
 fn shell(body: Html) -> Html {
     // req: html_safety/001 req: html_safety/002 req: axum_integration/001
-    hemx::page(&AppShell {
+    ui::page(&AppShell {
         runtime_src: runtime_js_path(),
         body,
     })
@@ -297,7 +297,7 @@ fn shell(body: Html) -> Html {
 
 fn render_options() -> Html {
     // req: html_safety/002 req: view/001
-    ui::render(&ColumnOptions {
+    ui::page(&ColumnOptions {
         options: COLUMNS
             .iter()
             .map(|(id, title)| ColumnOption { id, title })
@@ -385,7 +385,7 @@ mod tests {
             }],
         };
 
-        let html = ui::render(&board_view(&board));
+        let html = ui::page(&board_view(&board));
         let document = Html::parse_fragment(html.as_str());
         assert_eq!(
             document
@@ -417,7 +417,7 @@ mod tests {
     // req: html_safety/002 req: view/001 req: test/005
     #[test]
     fn presence_payload_is_rendered_by_a_hemplate_view() {
-        let html = ui::render(&Presence { count: 7 });
+        let html = ui::page(&Presence { count: 7 });
         let document = Html::parse_fragment(html.as_str());
         assert_eq!(
             document