feat(time-blocks): Add comprehensive time blocking system with contracts

- Add TimeBlock and Holiday models with recurrence support (one-time, weekly, monthly, yearly, holiday)
- Implement business-level and resource-level blocking with hard/soft block types
- Add multi-select holiday picker for bulk holiday blocking
- Add calendar overlay visualization with distinct colors:
  - Business blocks: Red (hard) / Yellow (soft)
  - Resource blocks: Purple (hard) / Cyan (soft)
- Add month view resource indicators showing 1/n width per resource
- Add yearly calendar view for block overview
- Add My Availability page for staff self-service
- Add contracts module with templates, signing flow, and PDF generation
- Update scheduler with click-to-day navigation in week view

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

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

smoothschedule/config/settings/multitenancy.py

@@ -56,6 +56,7 @@ TENANT_APPS = [
     'django.contrib.contenttypes',  # Needed for tenant schemas
     'schedule',  # Resource scheduling with configurable concurrency
     'payments',  # Stripe Connect payments bridge
+    'contracts',  # Contract/e-signature system
     # Add your tenant-scoped business logic apps here:
     # 'appointments',
     # 'customers',