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/ai/entitlements.ts

@@ -0,0 +1,14 @@
+import type { UserType } from "@/app/(auth)/auth";
+
+type Entitlements = {
+  maxMessagesPerHour: number;
+};
+
+export const entitlementsByUserType: Record<UserType, Entitlements> = {
+  guest: {
+    maxMessagesPerHour: 10,
+  },
+  regular: {
+    maxMessagesPerHour: 10,
+  },
+};