feat: Restructure notifications - Staff and Customer separation (WIP)
## 🎯 Phase 1: Backend + Frontend Structure
### Backend Changes
**NotificationsController.php:**
- ✅ Added `/notifications/staff/events` endpoint
- ✅ Added `/notifications/customer/events` endpoint
- ✅ Created `get_all_events()` helper method
- ✅ Added `recipient_type` field to all events
- ✅ Filter events by recipient (staff vs customer)
### Frontend Changes
**Main Notifications Page:**
- ✅ Restructured to show cards for Staff, Customer, Activity Log
- ✅ Entry point with clear separation
- ✅ Modern card-based UI
**Staff Notifications:**
- ✅ Created `/settings/notifications/staff` route
- ✅ Moved Channels.tsx → Staff/Channels.tsx
- ✅ Moved Events.tsx → Staff/Events.tsx
- ✅ Updated Staff/Events to use `/notifications/staff/events`
- ✅ Fixed import paths
### Structure
```
Settings → Notifications
├── Staff Notifications (admin alerts)
│ ├── Channels (Email, Push)
│ ├── Events (Orders, Products, Customers)
│ └── Templates
└── Customer Notifications (customer emails)
├── Channels (Email, Push, SMS)
├── Events (Orders, Shipping, Account)
└── Templates
```
---
**Next:** Customer notifications page + routes