feat: update AIUI dist (guide as default route) + fix marketplace heading clip

- Rebuild AIUI with guide page as default route (/ -> guide, /chat -> chat)
- Content and context panels start empty
- Fix App Store heading clipped by removing double md:-mt-4 negative margins

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

demo/aiui/assets/channel-BMNvF04a.js

@@ -0,0 +1 @@
+import{U as a,M as n}from"./mermaid.core-iePVYd9u.js";const t=(r,o)=>a.lang.round(n.parse(r)[o]);export{t as c};