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

components/chat/sidebar-toggle.tsx

@@ -0,0 +1,35 @@
+import type { ComponentProps } from "react";
+
+import { type SidebarTrigger, useSidebar } from "@/components/ui/sidebar";
+import {
+  Tooltip,
+  TooltipContent,
+  TooltipTrigger,
+} from "@/components/ui/tooltip";
+import { Button } from "../ui/button";
+import { SidebarLeftIcon } from "./icons";
+
+export function SidebarToggle({
+  className,
+}: ComponentProps<typeof SidebarTrigger>) {
+  const { toggleSidebar } = useSidebar();
+
+  return (
+    <Tooltip>
+      <TooltipTrigger asChild>
+        <Button
+          className={className}
+          data-testid="sidebar-toggle-button"
+          onClick={toggleSidebar}
+          size="icon-sm"
+          variant="outline"
+        >
+          <SidebarLeftIcon size={16} />
+        </Button>
+      </TooltipTrigger>
+      <TooltipContent align="start" className="hidden md:block">
+        Toggle Sidebar
+      </TooltipContent>
+    </Tooltip>
+  );
+}