feat: Add comprehensive sandbox mode, public API system, and platform support

This commit adds major features for sandbox isolation, public API access, and platform support ticketing.

## Sandbox Mode
- Add sandbox mode toggle for businesses to test features without affecting live data
- Implement schema-based isolation for tenant data (appointments, resources, services)
- Add is_sandbox field filtering for shared models (customers, staff, tickets)
- Create sandbox middleware to detect and set sandbox mode from cookies
- Add sandbox context and hooks for React frontend
- Display sandbox banner when in test mode
- Auto-reload page when switching between live/test modes
- Prevent platform support tickets from being created in sandbox mode

## Public API System
- Full REST API for external integrations with businesses
- API token management with sandbox/live token separation
- Test tokens (ss_test_*) show full plaintext for easy testing
- Live tokens (ss_live_*) are hashed and secure
- Security validation prevents live token plaintext storage
- Comprehensive test suite for token security
- Rate limiting and throttling per token
- Webhook support for real-time event notifications
- Scoped permissions system (read/write per resource type)
- API documentation page with interactive examples
- Token revocation with confirmation modal

## Platform Support
- Dedicated support page for businesses to contact SmoothSchedule
- View all platform support tickets in one place
- Create new support tickets with simplified interface
- Reply to existing tickets with conversation history
- Platform tickets have no admin controls (no priority/category/assignee/status)
- Internal notes hidden for platform tickets (business can't see them)
- Quick help section with links to guides and API docs
- Sandbox warning prevents ticket creation in test mode
- Business ticketing retains full admin controls (priority, assignment, internal notes)

## UI/UX Improvements
- Add notification dropdown with real-time updates
- Staff permissions UI for ticket access control
- Help dropdown in sidebar with Platform Guide, Ticketing Help, API Docs, and Support
- Update sidebar "Contact Support" to "Support" with message icon
- Fix navigation links to use React Router instead of anchor tags
- Remove unused language translations (Japanese, Portuguese, Chinese)

## Technical Details
- Sandbox middleware sets request.sandbox_mode from cookies
- ViewSets filter data by is_sandbox field
- API authentication via custom token auth class
- WebSocket support for real-time ticket updates
- Migration for sandbox fields on User, Tenant, and Ticket models
- Comprehensive documentation in SANDBOX_MODE_IMPLEMENTATION.md

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

smoothschedule/schedule/views.py

@@ -198,18 +198,21 @@ class CustomerViewSet(viewsets.ModelViewSet):
 
     def get_queryset(self):
         """
-        Return customers for the current tenant.
+        Return customers for the current tenant, filtered by sandbox mode.
 
         Customers are Users with role=CUSTOMER.
-        For now, return all customers. When authentication is enabled,
-        filter by the user's tenant.
+        In sandbox mode, only returns customers with is_sandbox=True.
+        In live mode, only returns customers with is_sandbox=False.
         """
         queryset = User.objects.filter(role=User.Role.CUSTOMER)
 
         # Filter by tenant if user is authenticated and has a tenant
-        # TODO: Re-enable this when authentication is enabled
-        # if self.request.user.is_authenticated and self.request.user.tenant:
-        #     queryset = queryset.filter(tenant=self.request.user.tenant)
+        if self.request.user.is_authenticated and self.request.user.tenant:
+            queryset = queryset.filter(tenant=self.request.user.tenant)
+
+        # Filter by sandbox mode - check request.sandbox_mode set by middleware
+        is_sandbox = getattr(self.request, 'sandbox_mode', False)
+        queryset = queryset.filter(is_sandbox=is_sandbox)
 
         # Apply status filter if provided
         status_filter = self.request.query_params.get('status')
@@ -231,6 +234,20 @@ class CustomerViewSet(viewsets.ModelViewSet):
 
         return queryset
 
+    def perform_create(self, serializer):
+        """
+        Set sandbox mode and tenant when creating a new customer.
+        """
+        is_sandbox = getattr(self.request, 'sandbox_mode', False)
+        tenant = None
+        if self.request.user.is_authenticated and self.request.user.tenant:
+            tenant = self.request.user.tenant
+        serializer.save(
+            role=User.Role.CUSTOMER,
+            is_sandbox=is_sandbox,
+            tenant=tenant,
+        )
+
 
 class ServiceViewSet(viewsets.ModelViewSet):
     """
@@ -308,9 +325,11 @@ class StaffViewSet(viewsets.ModelViewSet):
 
     def get_queryset(self):
         """
-        Return staff members for the current tenant.
+        Return staff members for the current tenant, filtered by sandbox mode.
 
         Staff are Users with roles: TENANT_OWNER, TENANT_MANAGER, TENANT_STAFF.
+        In sandbox mode, only returns staff with is_sandbox=True.
+        In live mode, only returns staff with is_sandbox=False.
         """
         from django.db.models import Q
 
@@ -331,6 +350,10 @@ class StaffViewSet(viewsets.ModelViewSet):
         # if self.request.user.is_authenticated and self.request.user.tenant:
         #     queryset = queryset.filter(tenant=self.request.user.tenant)
 
+        # Filter by sandbox mode - check request.sandbox_mode set by middleware
+        is_sandbox = getattr(self.request, 'sandbox_mode', False)
+        queryset = queryset.filter(is_sandbox=is_sandbox)
+
         # Apply search filter if provided
         search = self.request.query_params.get('search')
         if search: