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

hooks/use-chat-visibility.ts

@@ -0,0 +1,55 @@
+"use client";
+
+import { useMemo } from "react";
+import useSWR, { useSWRConfig } from "swr";
+import { unstable_serialize } from "swr/infinite";
+import { updateChatVisibility } from "@/app/(chat)/actions";
+import {
+  type ChatHistory,
+  getChatHistoryPaginationKey,
+} from "@/components/chat/sidebar-history";
+import type { VisibilityType } from "@/components/chat/visibility-selector";
+
+export function useChatVisibility({
+  chatId,
+  initialVisibilityType,
+}: {
+  chatId: string;
+  initialVisibilityType: VisibilityType;
+}) {
+  const { mutate, cache } = useSWRConfig();
+  const history: ChatHistory = cache.get(
+    `${process.env.NEXT_PUBLIC_BASE_PATH ?? ""}/api/history`
+  )?.data;
+
+  const { data: localVisibility, mutate: setLocalVisibility } = useSWR(
+    `${chatId}-visibility`,
+    null,
+    {
+      fallbackData: initialVisibilityType,
+    }
+  );
+
+  const visibilityType = useMemo(() => {
+    if (!history) {
+      return localVisibility;
+    }
+    const chat = history.chats.find((currentChat) => currentChat.id === chatId);
+    if (!chat) {
+      return "private";
+    }
+    return chat.visibility;
+  }, [history, chatId, localVisibility]);
+
+  const setVisibilityType = (updatedVisibilityType: VisibilityType) => {
+    setLocalVisibility(updatedVisibilityType);
+    mutate(unstable_serialize(getChatHistoryPaginationKey));
+
+    updateChatVisibility({
+      chatId,
+      visibility: updatedVisibilityType,
+    });
+  };
+
+  return { visibilityType, setVisibilityType };
+}