Employee delete: removed from list table (was broken due to row click
propagation), added as red button inside EmployeeShow with proper
wire:confirm and redirect after success.

Participant delete: removed from list table, added as red button inside
ParticipantShow that opens the DeleteParticipant modal with per-invoice
refund options. Redirects to list after deletion.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>