docs(kanban): describe delegated runtime attachment

Replace the north-star walkthrough's listener snippet with prose and guard example docs against teaching addEventListener glue.

req: examples/003

req: runtime/001

examples/kanban.md

@@ -285,15 +285,9 @@ Initial SSR:
 <!-- the app shell loads /slhx.js and any bootstrap state -->
 ```
 
-Runtime attachment:
-
-```js
-root.addEventListener("submit", dispatch)
-root.addEventListener("click", dispatch)
-root.addEventListener("pointerdown", dispatch)
-root.addEventListener("pointermove", dispatch)
-root.addEventListener("pointerup", dispatch)
-```
+Runtime attachment: `/slhx.js` installs delegated root listeners for forms,
+clicks, and pointer/drag events. App authors keep composing generated resources;
+they do not attach per-node listeners or write selector glue.
 
 No framework download. No VDOM. No hydration. No game loop.
 

slhx-test/tests/examples_contract.rs

@@ -117,6 +117,7 @@ fn canonical_example_docs_do_not_teach_low_level_plumbing() {
         "render_html(",
         "SafeHtml::trusted",
         ".render(&",
+        "addEventListener(",
     ];
     let mut failures = Vec::new();
     scan_examples(&examples, &mut |path, text| {