feat(harness): 用戶 CC harness（acr install-harness）+ 公開 repo 只留對外

讓「用 arcrun 開發」的用戶，他的 CC 自動載入 arcrun 防護、不退回自寫 Python。

新增 user-cc-harness（SDD: .agents/specs/user-cc-harness，本機）：
- acr install-harness：冪等裝進用戶當前專案（新/舊專案皆可），acr init 末尾也順便裝
  - CLAUDE.md arcrun 區塊（標記包夾，append 不破壞既有）
  - .claude/skills/arcrun-mindset（世界觀 + 資源去哪取 acr parts/auth-recipe）
  - .claude/commands/arcrun.md（/arcrun slash command）
  - .claude/hooks/arcrun-guard.sh（python→提醒不硬擋、暴露→exit 2、每條含正路）
  - settings.json 合併 hook（不覆蓋用戶既有 hooks/設定）
- llms.txt + README「給 AI」段：第一接觸點（用戶丟連結，CC 讀了知道第一步 install-harness）
  含 CF 憑證白話照抄式引導（不對用戶講 KV/Worker/R2 術語）
- harness 素材內嵌 npm 套件（cli/harness/，files 帶上），不依賴用戶有 arcrun repo
- 實測：空目錄/冪等/既有檔合併皆通過，tsc exit 0，npm pack 含 harness 5 檔

公開 repo 清理（richblack：用戶要用不要開發 arcrun）：
- git rm --cached 移除開發痕跡 + 思考過程出公開 repo（本機保留供 richblack 開發）：
  .claude/CLAUDE.md/AGENTS.md/.agents/docs/DECISIONS/BACKLOG/landing/.github
- .gitignore 防回流；補 MIT LICENSE

MCP（P7）納入 install-harness/update 的接點已設計，實作待 MCP 對齊（BACKLOG 另一條線）。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/user_requirements/arcrun-landing-page/components/chrome.jsx

@@ -1,92 +0,0 @@
-// Top nav and sidebar
-
-const TopNav = ({ onNav, current }) => {
-  const [scrolled, setScrolled] = React.useState(false);
-  React.useEffect(() => {
-    const onScroll = () => setScrolled(window.scrollY > 8);
-    window.addEventListener('scroll', onScroll);
-    return () => window.removeEventListener('scroll', onScroll);
-  }, []);
-  return (
-    <nav className={`topnav ${scrolled ? 'scrolled' : ''}`}>
-      <div className="flex gap-12" style={{alignItems: 'center'}}>
-        <Logo onClick={() => onNav('landing')} />
-        <div className="nav-links" style={{marginLeft: 20}}>
-          <a>Product</a>
-          <a>Docs</a>
-          <a>Pricing</a>
-          <a>Changelog</a>
-        </div>
-      </div>
-      <div className="flex gap-8" style={{alignItems: 'center'}}>
-        <button className="btn btn-ghost" onClick={() => onNav('auth')}>Log in</button>
-        <button className="btn btn-primary" onClick={() => onNav('auth')}>
-          Get started <Icon name="arrow_right" size={14} />
-        </button>
-      </div>
-    </nav>
-  );
-};
-
-const Footer = ({ onNav }) => (
-  <footer className="footer">
-    <div className="flex gap-12" style={{alignItems: 'center'}}>
-      <Logo size="sm" />
-      <span>© 2026 Arcrun Labs</span>
-    </div>
-    <div className="footer-links">
-      <a>Docs</a>
-      <a>Pricing</a>
-      <a>Changelog</a>
-      <a>Status</a>
-      <a>Privacy</a>
-    </div>
-  </footer>
-);
-
-// App shell with sidebar for logged-in screens
-const Sidebar = ({ current, onNav }) => {
-  const items = [
-    { id: 'dashboard', label: 'Dashboard', icon: 'home' },
-    { id: 'apps', label: 'Apps', icon: 'grid', count: 6 },
-    { id: 'workflows', label: 'Workflows', icon: 'workflow', count: 12 },
-    { id: 'keys', label: 'API Keys', icon: 'key' },
-    { id: 'docs', label: 'Docs', icon: 'book' },
-  ];
-  const bottom = [
-    { id: 'settings', label: 'Settings', icon: 'settings' },
-  ];
-  return (
-    <aside className="sidebar">
-      <div className="sidebar-head">
-        <Logo size="md" onClick={() => onNav('landing')} />
-      </div>
-      <div className="sidebar-section">Workspace</div>
-      {items.map(it => (
-        <div key={it.id}
-             className={`sidebar-item ${current === it.id ? 'active' : ''}`}
-             onClick={() => onNav(it.id)}>
-          <span className="sb-ico"><Icon name={it.icon} size={15} /></span>
-          <span>{it.label}</span>
-          {it.count != null && <span className="sb-count">{it.count}</span>}
-        </div>
-      ))}
-      <div style={{flex: 1}} />
-      {bottom.map(it => (
-        <div key={it.id} className="sidebar-item" onClick={() => onNav(it.id)}>
-          <span className="sb-ico"><Icon name={it.icon} size={15} /></span>
-          <span>{it.label}</span>
-        </div>
-      ))}
-      <div className="sidebar-foot">
-        <div className="avatar-circ">MR</div>
-        <div className="meta">
-          <div className="name">Maya Rivera</div>
-          <div className="email">maya@northwind.co</div>
-        </div>
-      </div>
-    </aside>
-  );
-};
-
-Object.assign(window, { TopNav, Footer, Sidebar });