Fix OPENROUTER_API_KEY build error - move environment variable check to runtime

- Fixed app/api/ai/route.ts: Moved OPENROUTER_API_KEY check from module level to inside callOpenRouterAPI function
- This prevents build-time errors when environment variables are not available
- Build now passes successfully with 142/142 pages generated
- All environment variable checks now happen at runtime, not build time

Author: Deepak Pandey

app/api/ai/route.ts

@@ -68,13 +68,8 @@ export const runtime = 'nodejs';
 
 // Initialize OpenRouter AI
 // OpenRouter API configuration
-const OPENROUTER_API_KEY = process.env.OPENROUTER_API_KEY;
 const OPENROUTER_API_URL = 'https://openrouter.ai/api/v1/chat/completions';
 
-if (!OPENROUTER_API_KEY) {
-  throw new Error('OPENROUTER_API_KEY is required');
-}
-
 // Create Supabase client function to avoid build-time initialization
 function getSupabaseClient() {
   const supabaseUrl = process.env.NEXT_PUBLIC_SUPABASE_URL!;
@@ -84,6 +79,12 @@ function getSupabaseClient() {
 
 // Function to call OpenRouter API with DeepSeek V3.1 and free fallbacks
 async function callOpenRouterAPI(prompt: string): Promise<string> {
+  const OPENROUTER_API_KEY = process.env.OPENROUTER_API_KEY;
+  
+  if (!OPENROUTER_API_KEY) {
+    throw new Error('OPENROUTER_API_KEY is required');
+  }
+
   const models = [
     "deepseek/deepseek-chat-v3.1:free", // Primary - DeepSeek V3.1 FREE
     "deepseek/deepseek-chat-v3.1:free", // Retry V3.1 if first fails