chore: remove internal docs from repo, update public documentation

Remove docs/superpowers/, .claude/ config, and PRD.md from version
control (kept locally via .gitignore). Update README, CHANGELOG,
VitePress docs, and .env.example to reflect recent features: Files
page, teams, admin settings, persistent storage, and various API
improvements.

apps/web/src/App.tsx

@@ -36,6 +36,7 @@ class ErrorBoundary extends Component<
               {this.state.error?.message || "An unexpected error occurred."}
             </p>
             <button
+              type="button"
               onClick={() => {
                 this.setState({ hasError: false, error: null });
                 window.location.href = "/";