docs: clarify OAuth as optional, document CONTAINER env var

- docker-compose: OAuth vars commented out by default
- env.example: added WordPress Advanced section with CONTAINER docs
- DOCKER_README: added CONTAINER to env var table with usage notes

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

env.example

@@ -37,7 +37,8 @@ WORDPRESS_SITE1_APP_PASSWORD=xxxx xxxx xxxx xxxx
 WORDPRESS_SITE1_ALIAS=mysite
 
 # Optional: Docker container name for WP-CLI tools (cache flush, transients, etc.)
-# Find with: docker ps --filter name=wordpress
+# Find your container name with: docker ps --filter name=wordpress
+# This lets MCP Hub run wp-cli commands inside your WordPress container.
 # WORDPRESS_SITE1_CONTAINER=wordpress-container-name
 
 # Second site example (uncomment to use):
@@ -46,6 +47,20 @@ WORDPRESS_SITE1_ALIAS=mysite
 # WORDPRESS_SITE2_APP_PASSWORD=yyyy yyyy yyyy yyyy
 # WORDPRESS_SITE2_ALIAS=blog
 
+# ============================================
+# WORDPRESS ADVANCED (database, bulk, system)
+# ============================================
+# Pattern: WORDPRESS_ADVANCED_{SITE_ID}_{CONFIG_KEY}
+# Provides database operations, bulk operations, and system management.
+# REQUIRES Docker socket AND container name — all tools use WP-CLI.
+#
+# Uses the same credentials as WordPress, but the CONTAINER key is REQUIRED.
+# WORDPRESS_ADVANCED_SITE1_URL=https://your-site.com
+# WORDPRESS_ADVANCED_SITE1_USERNAME=admin
+# WORDPRESS_ADVANCED_SITE1_APP_PASSWORD=xxxx xxxx xxxx xxxx
+# WORDPRESS_ADVANCED_SITE1_CONTAINER=wordpress-container-name
+# WORDPRESS_ADVANCED_SITE1_ALIAS=mysite-advanced
+
 # ============================================
 # WOOCOMMERCE STORES
 # ============================================