fix: lazy-init OpenAI client to avoid build failure without API key

.env.example

@@ -0,0 +1,6 @@
+DATABASE_URL=postgresql://postgres:postgres@localhost:5432/comparaison
+BETTER_AUTH_SECRET=change-me-to-random-string
+OPENAI_API_KEY=
+PERPLEXITY_API_KEY=
+TAVILY_API_KEY=
+NEXT_PUBLIC_APP_URL=http://localhost:3000

.gitignore

@@ -32,6 +32,7 @@ yarn-error.log*
 
 # env files (can opt-in for committing if needed)
 .env*
+!.env.example
 
 # vercel
 .vercel

next.config.ts

@@ -1,7 +1,7 @@
 import type { NextConfig } from "next";
 
 const nextConfig: NextConfig = {
-  /* config options here */
+  output: "standalone",
 };
 
 export default nextConfig;

src/lib/llm/providers/openai.ts

@@ -6,9 +6,14 @@ import type {
   ItemResearch,
 } from "../types";
 
-const client = new OpenAI({
-  apiKey: process.env.OPENAI_API_KEY,
-});
+let _client: OpenAI | null = null;
+
+function getClient(): OpenAI {
+  if (!_client) {
+    _client = new OpenAI({ apiKey: process.env.OPENAI_API_KEY });
+  }
+  return _client;
+}
 
 const SYSTEM_PROMPT = `You are an expert research analyst. Your job is to compare items across multiple dimensions and produce structured, insightful comparison data.
 
@@ -105,7 +110,7 @@ Provide a comprehensive comparison with scores, pros/cons, and a recommendation.
 
   for (let attempt = 1; attempt <= MAX_RETRIES; attempt++) {
     try {
-      const response = await client.chat.completions.create({
+      const response = await getClient().chat.completions.create({
         model: "gpt-4o-mini",
         messages: [
           { role: "system", content: SYSTEM_PROMPT },