docs: Update .env.local.example with new environment variables

Added NEXT_PUBLIC_GITHUB_TOKEN and NEXT_PUBLIC_WEBHOOK_LOGIN to the example
environment file to reflect recent additions to the project configuration.
Also included comments for local-only and production-only variables.

Author: OnCloud125252

.env.local.example

@@ -1,8 +1,23 @@
+# Google OAuth
 GOOGLE_CLIENT_ID=
 GOOGLE_CLIENT_SECRET=
+
+# Backend
+NEXT_PUBLIC_API_URL=
+
+# NextAuth
 NEXTAUTH_URL=
 NEXTAUTH_SECRET=
-NEXT_PUBLIC_API_URL=
-NODE_ENV=development,no-strict
 
-NEXT_PUBLIC_WEBHOOK_LOGIN=
+# GitHub token that have read access to MingdaoSIG-Frontend repo
+NEXT_PUBLIC_GITHUB_TOKEN=
+
+# Discord webhook URL for displaying login log
+NEXT_PUBLIC_WEBHOOK_LOGIN=
+
+# Local Only
+# NODE_ENV=development,no-strict
+
+# Production Only
+# FORCE_CONTAINERIZED=1
+# NODE_OPTIONS=--max-old-space-size=512