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/components/help/help-dialog.tsx

@@ -36,13 +36,18 @@ export function HelpDialog({ open, onClose }: HelpDialogProps) {
 
   return (
     <div className="fixed inset-0 z-50 flex items-center justify-center">
-      <div className="absolute inset-0 bg-black/50 backdrop-blur-sm" onClick={onClose} />
+      <div
+        aria-hidden="true"
+        className="absolute inset-0 bg-black/50 backdrop-blur-sm cursor-default"
+        onClick={onClose}
+      />
 
       <div className="relative bg-background border border-border rounded-xl shadow-2xl w-full max-w-lg max-h-[85vh] flex flex-col overflow-hidden">
         {/* Header */}
         <div className="flex items-center justify-between p-4 border-b border-border shrink-0">
           <h2 className="text-lg font-semibold text-foreground">Help</h2>
           <button
+            type="button"
             onClick={onClose}
             className="p-1.5 rounded-lg hover:bg-muted transition-colors text-muted-foreground hover:text-foreground"
           >