fix(frontend): replace hardcoded localhost with environment variable

frontend/.env.example

@@ -0,0 +1,12 @@
+# Frontend Environment Variables
+# Copy this to .env.local for local development overrides
+
+# Backend API URL
+# Production: Set in Vercel dashboard (e.g., https://codeintel-backend.railway.app)
+# Development: Defaults to http://localhost:8000 (Docker Compose)
+VITE_API_URL=http://localhost:8000
+
+# Supabase Configuration
+# Get these from your Supabase project settings
+VITE_SUPABASE_URL=https://your-project.supabase.co
+VITE_SUPABASE_ANON_KEY=your-anon-key-here

frontend/src/components/Dashboard.tsx

@@ -12,8 +12,7 @@ import { ImpactAnalyzer } from './ImpactAnalyzer'
 import { PerformanceDashboard } from './PerformanceDashboard'
 import { UserNav } from './UserNav'
 import type { Repository } from '../types'
-
-const API_URL = 'http://localhost:8000'
+import { API_URL } from '../config/api'
 
 type RepoTab = 'overview' | 'search' | 'dependencies' | 'insights' | 'impact'
 

frontend/src/config/api.ts

@@ -0,0 +1,13 @@
+/**
+ * API Configuration
+ * 
+ * Centralizes API URL configuration for all frontend components.
+ * 
+ * - Production: Set VITE_API_URL in Vercel dashboard to Railway backend URL
+ * - Development: Defaults to localhost:8000 (Docker Compose)
+ * - Local dev without Docker: Can override with .env.local
+ */
+
+const API_URL = import.meta.env.VITE_API_URL || 'http://localhost:8000'
+
+export { API_URL }