Initial commit: EGBE chatbot template

Stripped from vercel/chatbot (Apache 2.0):
- Dropped @vercel/* packages and AI Gateway
- Removed artifacts feature (code/text/sheet/image side panel)
- Switched AI provider to @ai-sdk/openai-compatible -> EGBE LiteLLM
- Replaced Vercel Blob upload with data URLs
- Dropped Redis resumable streams and rate limiter (in-memory now)
- Added Dockerfile (Next.js standalone) + entrypoint that runs migrations
- Wired DATABASE_URL, EGBE_AI_API_URL/KEY, NEXT_PUBLIC_BASE_URL for app-deploy.sh

app/(chat)/layout.tsx

@@ -0,0 +1,46 @@
+import { cookies } from "next/headers";
+import { Suspense } from "react";
+import { Toaster } from "sonner";
+import { AppSidebar } from "@/components/chat/app-sidebar";
+import { DataStreamProvider } from "@/components/chat/data-stream-provider";
+import { ChatShell } from "@/components/chat/shell";
+import { SidebarInset, SidebarProvider } from "@/components/ui/sidebar";
+import { ActiveChatProvider } from "@/hooks/use-active-chat";
+import { auth } from "../(auth)/auth";
+
+export default function Layout({ children }: { children: React.ReactNode }) {
+  return (
+    <DataStreamProvider>
+      <Suspense fallback={<div className="flex h-dvh bg-sidebar" />}>
+        <SidebarShell>{children}</SidebarShell>
+      </Suspense>
+    </DataStreamProvider>
+  );
+}
+
+async function SidebarShell({ children }: { children: React.ReactNode }) {
+  const [session, cookieStore] = await Promise.all([auth(), cookies()]);
+  const isCollapsed = cookieStore.get("sidebar_state")?.value !== "true";
+
+  return (
+    <SidebarProvider defaultOpen={!isCollapsed}>
+      <AppSidebar user={session?.user} />
+      <SidebarInset>
+        <Toaster
+          position="top-center"
+          theme="system"
+          toastOptions={{
+            className:
+              "!bg-card !text-foreground !border-border/50 !shadow-[var(--shadow-float)]",
+          }}
+        />
+        <Suspense fallback={<div className="flex h-dvh" />}>
+          <ActiveChatProvider>
+            <ChatShell />
+          </ActiveChatProvider>
+        </Suspense>
+        {children}
+      </SidebarInset>
+    </SidebarProvider>
+  );
+}