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/data-stream-provider.tsx

@@ -0,0 +1,41 @@
+"use client";
+
+import type { DataUIPart } from "ai";
+import type React from "react";
+import { createContext, useContext, useMemo, useState } from "react";
+import type { CustomUIDataTypes } from "@/lib/types";
+
+type DataStreamContextValue = {
+  dataStream: DataUIPart<CustomUIDataTypes>[];
+  setDataStream: React.Dispatch<
+    React.SetStateAction<DataUIPart<CustomUIDataTypes>[]>
+  >;
+};
+
+const DataStreamContext = createContext<DataStreamContextValue | null>(null);
+
+export function DataStreamProvider({
+  children,
+}: {
+  children: React.ReactNode;
+}) {
+  const [dataStream, setDataStream] = useState<DataUIPart<CustomUIDataTypes>[]>(
+    []
+  );
+
+  const value = useMemo(() => ({ dataStream, setDataStream }), [dataStream]);
+
+  return (
+    <DataStreamContext.Provider value={value}>
+      {children}
+    </DataStreamContext.Provider>
+  );
+}
+
+export function useDataStream() {
+  const context = useContext(DataStreamContext);
+  if (!context) {
+    throw new Error("useDataStream must be used within a DataStreamProvider");
+  }
+  return context;
+}