Implement WHMCS Addon Dashboard with API for stats and integrate billing provider logic

integrations/whmcs/modules/addons/hexagamecloud/README.md

@@ -1,7 +1,36 @@
-# Addon module placeholder
+# WHMCS addon module
 
-Implementation planned in WHMCS Phase A.
+Install path: `/modules/addons/hexagamecloud/`
 
-Target install path: `/modules/addons/hexagamecloud/`
+## Features
 
-Handles global API settings, product mappings, reconciliation, and event polling.
+- **Dashboard** — API health, linked services, pending events, reconciliation summary
+- **Events** — Poll GameCloud cursor events, local cache, manual ack / dead-letter
+- **Reconciliation** — Dry-run and live runs with optional auto-repair
+- **Daily cron** — Copy `integrations/whmcs/hooks/hexagamecloud.php` to WHMCS `includes/hooks/`
+
+## Setup
+
+1. Activate **Addon Modules → HexaHost GameCloud**
+2. Configure API URL, Integration ID, API Secret (same as GameCloud `WHMCS_*` seed values)
+3. Copy the hook file for automated polling
+4. Open **Addons → HexaHost GameCloud** for the dashboard
+
+## Tables
+
+Created on activation (`sql/install.sql`):
+
+- `mod_hexagamecloud_installations`
+- `mod_hexagamecloud_sync_cursors`
+- `mod_hexagamecloud_events`
+- `mod_hexagamecloud_operations`
+- `mod_hexagamecloud_reconciliation`
+
+## API used
+
+- `GET /integrations/whmcs/dashboard/stats`
+- `GET /integrations/whmcs/accounts`
+- `GET /integrations/whmcs/events` + `POST .../events/ack`
+- `POST /integrations/whmcs/reconcile`
+
+See [docs/integrations/whmcs/addon-module.md](../../../../docs/integrations/whmcs/addon-module.md).