feat(analytics): add SEO/GEO page dashboard and retire Rybbit SSO

Expose Umami memind-pages discoveryChannel data in adm with a public-page
style table, proxy it via admin-api, and remove Rybbit configuration paths.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/admin/AdminNav.tsx

@@ -33,6 +33,7 @@ const NAV_SECTIONS: NavSection[] = [
       { to: '/wechat', label: '服务号' },
       { to: '/mindspace', label: 'MindSpace 配置' },
       { to: '/analytics', label: 'Analytics 配置' },
+      { to: '/analytics/seo-geo', label: 'SEO / GEO 流量' },
       { to: '/memory-v2', label: 'Memory V2' },
       { to: '/mindsearch', label: 'MindSearch' },
       { to: '/skill-runtime', label: 'Skill Runtime' },