feat(hemx): clarify generated authoring path

Close the fallible handler and example coherence slice: v0 uses typed todo newtypes, Result handler failure mapping, generated form/partial helpers, and page composition; kanban is explicitly marked as an advanced north-star milestone; raw render is isolated behind hemx::advanced::render.

req: canonical_authoring/003

req: failure/004

req: public_api/005

req: examples/004

examples/kanban/README.md

@@ -1,4 +1,6 @@
-# hemx Kanban browser example
+# hemx Kanban advanced milestone example
+
+This is an explicitly advanced/low-level north-star boundary sketch, not beginner-facing guidance. It exercises the product boundary described in `../kanban.md`; use `examples/v0` for the canonical beginner path.
 
 Run:
 

examples/kanban/src/main.rs

@@ -288,7 +288,7 @@ fn page_html(board: &BoardState) -> Html {
 
 fn shell(body: Html) -> Html {
     // req: html_safety/001 req: html_safety/002 req: axum_integration/001
-    hemx::render(&AppShell { body })
+    hemx::page(&AppShell { body })
 }
 
 fn render_options() -> Html {
@@ -332,12 +332,12 @@ fn render_card(card: &Card) -> BoardCard {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use scraper::{Html, Selector};
     use hemx_test::{
         class_child_selector, disabled_button_selector, element_class_selector,
         escaped_markup_selector, form_selector, keyed_selector, root_element_selector,
         select_options_selector, small_text_selector, strong_text_selector,
     };
+    use scraper::{Html, Selector};
 
     fn selector(value: &str) -> Selector {
         Selector::parse(value).expect("test selector parses")