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

drizzle.config.ts

@@ -0,0 +1,15 @@
+import { config } from "dotenv";
+import { defineConfig } from "drizzle-kit";
+
+config({
+  path: ".env.local",
+});
+
+export default defineConfig({
+  schema: "./lib/db/schema.ts",
+  out: "./lib/db/migrations",
+  dialect: "postgresql",
+  dbCredentials: {
+    url: process.env.DATABASE_URL ?? "",
+  },
+});