BookingWP WooCommerce Appointments

## What's New
- WooCommerce Core Compatibility: Tested and fully verified for seamless operation with the latest WooCommerce core releases.
- Extended PHP & WordPress Support: Refactored internal functions to maintain full compatibility with recent WordPress releases and modern PHP 8.x environments.

## Tweaks & Improvements
- Availability & Slot Calculation Performance: Refactored backend query loops when retrieving staff availability and multi-slot time rules on single product appointment forms.
- Google Calendar Sync Reliability: Enhanced two-way synchronization workflows to handle sudden API rate-limiting and ensure faster calendar status updates.

## Bug Fixes
- Time Slot Cost Calculation: Fixed an issue where selecting specific appointment slots on the product frontend occasionally miscalculated overall booking costs.
- Add-Ons Saving & Calculations: Resolved a bug where custom product add-on field values intermittently failed to save during multi-appointment checkout flows.
- Admin Staff Filter Overlap: Fixed an administrative dashboard filtering bug where assigned staff members were incorrectly displayed on unrelated appointment calendar views.
- Mobile Calendar Picker Layout: Corrected CSS layout glitches where interactive calendar date pickers clipped action triggers on narrow smartphone viewports.

## What's New
- Extended WooCommerce Core Compatibility: Updated internal booking logic and checkout hooks to ensure full synchronization with the latest WooCommerce core releases.
- Optimized Slot Availability Calculations: Refactored time-slot availability parsing algorithms to accelerate calendar loading speeds for high-volume service schedules.

## Tweaks & Improvements
- Improved Calendar UI Fluidity: Refactored admin and frontend appointment calendar scripts for smoother date navigation and clearer status indicator overlays.
- Flexible Staff Availability Overrides: Enhanced custom staff working hours logic to allow easier configuration of holiday schedules and localized break intervals.

## Bug Fixes
- Time Zone Conversion Offset: Fixed an issue where appointment start times occasionally shifted by an hour on customer confirmation screens under specific server time zones.
- Multi-Staff Booking Lockout: Resolved a database concurrency bug where simultaneous bookings for different staff members under the same slot caused temporary scheduling overlaps.
- Google Calendar Sync Refresh Loop: Corrected an OAuth token refresh error that occasionally interrupted two-way Google Calendar synchronization on high-frequency update loops.
- Cart Drawer Price Calculation: Fixed a dynamic checkout issue where custom appointment addon fees failed to update immediately in off-canvas WooCommerce cart drawers.