Implement Phase 7: Contact Form 7 Integration (v0.7.0)

Add custom CF7 form tags for booking requests:
- [bnb_building_select] - Building filter dropdown
- [bnb_room_select] - Room selection with capacity data
- [bnb_date_checkin/checkout] - Date pickers with validation
- [bnb_guests] - Guest count with capacity limits

Features:
- Server-side validation for all fields
- Real-time AJAX availability checking
- Automatic price calculation display
- Booking creation on form submission
- Guest record creation/linking
- Custom mail tags for CF7 templates

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

PLAN.md

@@ -149,20 +149,20 @@ This document outlines the implementation plan for the WP BnB Management plugin.
 - [x] Building rooms widget
 - [x] Availability calendar widget
 
-## Phase 7: Contact Form 7 Integration (v0.7.0)
+## Phase 7: Contact Form 7 Integration (v0.7.0) - Complete
 
 ### Booking Request Form
 
-- [ ] Custom CF7 tags for rooms/dates
-- [ ] Form validation
-- [ ] Booking creation on submission
-- [ ] Email notifications
+- [x] Custom CF7 tags for rooms/dates
+- [x] Form validation
+- [x] Booking creation on submission
+- [x] Email notifications
 
 ### Inquiry Form
 
-- [ ] General inquiry handling
-- [ ] Room-specific inquiries
-- [ ] Auto-response templates
+- [x] General inquiry handling
+- [x] Room-specific inquiries
+- [x] Auto-response templates (uses default CF7 mail templates)
 
 ## Phase 8: Dashboard & Reports (v0.8.0)
 
@@ -306,7 +306,7 @@ The plugin will provide extensive hooks for customization:
 | 0.4.0   | Guests             | Complete |
 | 0.5.0   | Services           | Complete |
 | 0.6.0   | Frontend           | Complete |
-| 0.7.0   | CF7 Integration    | TBD      |
+| 0.7.0   | CF7 Integration    | Complete |
 | 0.8.0   | Dashboard          | TBD      |
 | 0.9.0   | Prometheus Metrics | TBD      |
 | 0.10.0  | Security Audit     | TBD      |