feat: add /ai nav entry; pre-bundle arcadia/phoenix deps to fix 504s

Adds an "AI" item to the sidebar nav (mirrors Vibespace's /ai route,
already wired in routes.ts). vite.config.ts now lists openapi-fetch,
phoenix, lucide-react, clsx, tailwind-merge, class-variance-authority
in optimizeDeps.include and adds explicit resolve.alias entries for
the arcadia and crema sibling libs so Vite resolves them on first
load instead of triggering a re-optimize mid-session.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/components/layout/app-shell.tsx

@@ -89,6 +89,7 @@ const navItems: NavItem[] = [
   { to: "/", icon: LayoutDashboard, label: "Overview", end: true },
   { to: "/tenants", icon: Building2, label: "Tenants" },
   { to: "/activity", icon: Activity, label: "Audit log" },
+  { to: "/ai", icon: Bot, label: "AI" },
   { to: "/settings", icon: Settings, label: "Settings" },
   // CREMA:NAV-ITEMS
 ]