feat: add agent-authored code walkthroughs (#1647)

* feat: add code-walkthrough backend (MCP tool, service, persistence, WS events)

* feat: render agent code walkthroughs as line-anchored cards + editor window

* test: add code-walkthrough re-emit mock-agent scenario

* fix: rework code-walkthrough UX (floating card, line reveal, minimize, clickable file)

* fix: improve code walkthrough editor UX

* fix: backfill walkthrough launcher after websocket connect

* fix: improve walkthrough requests and editor anchors

* fix: clear walkthrough highlights on close

* feat: add walkthrough discard and prompt customization

* fix: send walkthrough requests through saved prompt

* fix: support postgres built-in prompt seeding

* fix: address walkthrough review feedback

* fix: address walkthrough review follow-ups

* fix: harden walkthrough lifecycle races

* fix: reuse walkthrough notification cleanup

* fix: guard stale walkthrough file opens

* fix: abort stale file opens before paint

* fix: stabilize github settings e2e readiness

* fix: use stable github settings e2e selector

apps/web/components/github/github-settings.tsx

@@ -271,7 +271,10 @@ export function GitHubConnectionSection() {
   return (
     <>
       <div>
-        <h2 className="text-2xl font-bold flex items-center gap-2">
+        <h2
+          className="text-2xl font-bold flex items-center gap-2"
+          data-testid="github-integration-heading"
+        >
           <IconBrandGithub className="h-6 w-6" />
           GitHub Integration
         </h2>