feat: Add WooCommerce, cron, and transient metrics (v0.2.0)

- WooCommerce integration metrics (products, orders, revenue, customers)
- Cron job metrics (events by hook, overdue count, next run timestamp)
- Transient cache metrics (total, expiring, expired)
- Support for WooCommerce HPOS storage
- Updated settings page with new metric categories
- Updated translations and documentation

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CLAUDE.md

@@ -15,6 +15,9 @@ This plugin provides a Prometheus `/metrics` endpoint and an extensible way to a
 - Prometheus compatible authenticated `/metrics` endpoint
 - Optional default metrics (users, posts, comments, plugins)
 - Runtime metrics (HTTP requests, request duration, database queries)
+- Cron job metrics (scheduled events, overdue, next run)
+- Transient cache metrics (total, expiring, expired)
+- WooCommerce integration (products, orders, revenue, customers)
 - Dedicated plugin settings under 'Settings/Metrics' menu
 - Extensible by other plugins using `wp_prometheus_collect_metrics` action hook
 - License management integration
@@ -27,11 +30,11 @@ This project is proudly **"vibe-coded"** using Claude.AI - the entire codebase w
 
 **Note for AI Assistants:** Clean this section after the specific features are done or new releases are made. Effective changes are tracked in `CHANGELOG.md`. Do not add completed versions here - document them in the Session History section at the end of this file.
 
-### Version 0.2.0 (Planned)
+### Version 0.3.0 (Planned)
 
-- WooCommerce integration metrics
-- Cron job metrics
-- Transient cache metrics
+- Custom metric builder in admin
+- Metric export/import
+- Grafana dashboard templates
 
 ## Technical Stack
 
@@ -282,6 +285,28 @@ add_action( 'wp_prometheus_collect_metrics', function( $collector ) {
 
 ## Session History
 
+### 2026-02-02 - Extended Metrics (v0.2.0)
+
+- Added WooCommerce integration metrics (only when WooCommerce is active):
+  - `wordpress_woocommerce_products_total` - Products by status and type
+  - `wordpress_woocommerce_orders_total` - Orders by status
+  - `wordpress_woocommerce_revenue_total` - Revenue (all time, today, month)
+  - `wordpress_woocommerce_customers_total` - Customers (registered, guest)
+- Added cron job metrics:
+  - `wordpress_cron_events_total` - Scheduled cron events by hook (top 20)
+  - `wordpress_cron_overdue_total` - Number of overdue cron events
+  - `wordpress_cron_next_run_timestamp` - Unix timestamp of next scheduled cron
+- Added transient cache metrics:
+  - `wordpress_transients_total` - Transients by type (total, with_expiration, persistent, expired)
+- Updated Settings page with new metric categories
+- Updated Help tab with new metrics reference
+- **Key Learning**: WooCommerce HPOS (High-Performance Order Storage) requires different queries
+  - Check `OrderUtil::custom_orders_table_usage_is_enabled()` to determine storage type
+  - HPOS uses `wc_orders` table instead of `posts` and `postmeta`
+- **Key Learning**: Cron event labeling requires cardinality control
+  - Limit to top 20 hooks to prevent label explosion
+  - Use `arsort()` to get most frequent hooks first
+
 ### 2026-02-02 - Runtime Metrics (v0.1.0)
 
 - Implemented runtime metrics collection for HTTP requests and database queries