feat: demo deployment with AIUI chat, SSH key auth, Quick Start fix

- Add AIUI pre-built dist to demo/ for Portainer deployment
- Add nginx-demo.conf with Claude API proxy (envsubst for API key)
- Add docker-entrypoint.sh for runtime API key injection
- Update Dockerfile.web to include AIUI and Claude proxy
- Update docker-compose.demo.yml with ANTHROPIC_API_KEY env var
- Switch deploy script from sshpass to SSH key auth
- Fix Quick Start Goals animating before other cards (stagger 5, opacity guard)

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

demo/aiui/assets/classDiagram-v2-WZHVMYZB-BR9StYyX.js

@@ -0,0 +1 @@
+import{s as a,c as s,a as e,C as t}from"./chunk-B4BG7PRW-Xp_L3JSR.js";import{_ as i}from"./mermaid.core-CAd6zjbx.js";import"./chunk-FMBD7UC4-Ckq4i3s7.js";import"./chunk-55IACEB6-wvCzuWU8.js";import"./chunk-QN33PNHL-DwbD-drI.js";import"./index-CqBtvLD5.js";var u={parser:e,get db(){return new t},renderer:s,styles:a,init:i(r=>{r.class||(r.class={}),r.class.arrowMarkerAbsolute=r.arrowMarkerAbsolute},"init")};export{u as diagram};