Fix 5 support ticket bugs: AJAX errors, capacity validation, audit export, player lookup, fee display

TKT-59: ExceptionHandler now returns JSON for AJAX/XHR requests instead of
HTML error pages. Booking wizard JS improved to show actual error messages.

TKT-57: Pricing rule creation now validates group_size_max against the
facility unit's max_capacity, preventing over-capacity rules.

TKT-46: Added audit log CSV export with all current filters applied.
New route GET /audit/export and export button in the filter bar.

TKT-55: Player registration member lookup now uses only the DB id
(set by AJAX member lookup) instead of ambiguous membership_number/id
fallback. National ID field locked when auto-filled from member record.

TKT-50: Fee breakdown text now shows base amount and development fee
separately (e.g. "اشتراك سنوي: 222.00 + تنمية: 35.00 = 257.00")
instead of just the combined total.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>