Issue #4: Pagination logic was repeated across multiple routes.
Changes:
- Add pagination.py with reusable utilities:
- calculate_total_pages: computes page count from total/per_page
- calculate_offset: computes offset for given page
- create_paginated_response: builds PaginatedResponse with metadata
- Update routes/audit.py to use pagination utilities
- Update routes/booking.py to use pagination utilities
- Update routes/invites.py to use pagination utilities
The utilities handle the common pagination math while routes
still manage their own query logic (filters, joins, ordering).
