Add guide and evals for context-sensitive sticky headers

guides/dev-guide.ts

@@ -339,6 +339,7 @@ async function runAgentTest(targetDir: string, guideName: string, guidedOnly = f
     numRuns: 1,
     skipEval: true,
     guidedOnly,
+    suiteConfig,
   });
 
   // 3. Grade agent output (unguided + guided)

guides/user-experience/state-aware-sticky-headers/expectations.md

@@ -0,0 +1,7 @@
+- The header container uses `position: sticky` to remain at the top of the scroller.
+- The header container defines `container-type: scroll-state` to enable scroll state queries.
+- The header container defines `container-name: section-header` to avoid collisions.
+- The header visual style changes (e.g., background color or box-shadow) when it is stuck at the top.
+- The visual style changes are implemented using the `@container scroll-state(stuck: top)` query.
+- A functional JavaScript fallback using `IntersectionObserver` is provided for browsers that do not support scroll-state queries.
+- The fallback markup and script must be present in the rendered output.