Add environment configuration template for sensitive data

.env.example

@@ -0,0 +1,9 @@
+# Email Configuration
+CONTACT_EMAIL=your-email@gmail.com
+
+# Google reCAPTCHA
+RECAPTCHA_SITE_KEY=your-site-key-here
+RECAPTCHA_SECRET_KEY=your-secret-key-here
+
+# Rate Limiting (requests per hour)
+RATE_LIMIT=10