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

lib/utils.ts

@@ -0,0 +1,77 @@
+import type {
+  UIMessage,
+  UIMessagePart,
+} from 'ai';
+import { type ClassValue, clsx } from 'clsx';
+import { formatISO } from 'date-fns';
+import { twMerge } from 'tailwind-merge';
+import type { DBMessage } from '@/lib/db/schema';
+import { ChatbotError, type ErrorCode } from './errors';
+import type { ChatMessage, ChatTools, CustomUIDataTypes } from './types';
+
+export function cn(...inputs: ClassValue[]) {
+  return twMerge(clsx(inputs));
+}
+
+export const fetcher = async (url: string) => {
+  const response = await fetch(url);
+
+  if (!response.ok) {
+    const { code, cause } = await response.json();
+    throw new ChatbotError(code as ErrorCode, cause);
+  }
+
+  return response.json();
+};
+
+export async function fetchWithErrorHandlers(
+  input: RequestInfo | URL,
+  init?: RequestInit,
+) {
+  try {
+    const response = await fetch(input, init);
+
+    if (!response.ok) {
+      const { code, cause } = await response.json();
+      throw new ChatbotError(code as ErrorCode, cause);
+    }
+
+    return response;
+  } catch (error: unknown) {
+    if (typeof navigator !== 'undefined' && !navigator.onLine) {
+      throw new ChatbotError('offline:chat');
+    }
+
+    throw error;
+  }
+}
+
+export function generateUUID(): string {
+  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, (c) => {
+    const r = (Math.random() * 16) | 0;
+    const v = c === 'x' ? r : (r & 0x3) | 0x8;
+    return v.toString(16);
+  });
+}
+
+export function sanitizeText(text: string) {
+  return text.replace('<has_function_call>', '');
+}
+
+export function convertToUIMessages(messages: DBMessage[]): ChatMessage[] {
+  return messages.map((message) => ({
+    id: message.id,
+    role: message.role as 'user' | 'assistant' | 'system',
+    parts: message.parts as UIMessagePart<CustomUIDataTypes, ChatTools>[],
+    metadata: {
+      createdAt: formatISO(message.createdAt),
+    },
+  }));
+}
+
+export function getTextFromMessage(message: ChatMessage | UIMessage): string {
+  return message.parts
+    .filter((part) => part.type === 'text')
+    .map((part) => (part as { type: 'text'; text: string}).text)
+    .join('');
+}