feature/entra id authentication added

.env.example

@@ -14,3 +14,15 @@ OPENAI_MODEL=gpt-4-turbo-preview
 MAX_TOKENS=4000
 TEMPERATURE=0.7
 FRONTEND_URL=http://localhost:3000
+
+# Microsoft Entra ID (Azure AD)
+# Create an app registration at: https://portal.azure.com/#view/Microsoft_AAD_RegisteredApps
+# Add redirect URI: http://localhost:3000/auth/callback
+ENTRA_TENANT_ID=your-tenant-id
+ENTRA_CLIENT_ID=your-client-id
+ENTRA_CLIENT_SECRET=your-client-secret
+ENTRA_REDIRECT_URI=http://localhost:3000/auth/callback
+
+# JWT Configuration
+JWT_SECRET=change-this-to-a-secure-random-string
+JWT_EXPIRY_HOURS=24