v1.8: FastAdmin chathub-addon — register/plan/payment/member-center + 5 channel bindings

- New fastadmin/chathub/ (11 files, 204K): user-facing FastAdmin ThinkPHP 5 addon
- _markOrderPaid() now calls _provisionAsync() on empty embed_code (closes 'paid but no code' gap)
- New reprovision() action — user-initiated resource rebuild
- payReturn() smart redirect: 3 branches (just_paid / provisioning / pending / fallback)
- status badge updated with 'provisioning' state (blue)
- _initialize() whitelist expanded: reprovision (user) + payNotify/payReturn (public webhook)
- 5 chathub_* tables (tenant/log/order/channel_account/gateway_log) + MIGRATIONS.md

Bugfixes during E2E:
- payNotify HTTP 500: tenant.status ENUM missing 'provisioning' value (DBA migration)
- payNotify HTTP 500: chathub_log.status='received' (not in ENUM) — changed to 'success'
- TP5 method signature: function reprovision(\$ids) does not read query string — use \$this->request->param('ids')

fastadmin/chathub/info.ini

@@ -0,0 +1,7 @@
+name = chathub
+title = ChatHub 租户管理
+intro = Chatwoot AI客服系统租户管理平台，支持多租户开通、配置管理、状态监控
+author = GreatQiu
+website = https://github.com/hanmolabiqiu/chatwoot-ai-agent
+version = 1.0.0
+state = 1