feat: complete promoter payout system implementation

- Add comprehensive payout styling with custom CSS classes for status indicators
- Implement payout index and show views with French translations
- Add payout migration with proper indexes and defaults
- Update database schema with payout-related tables and fields
- Add comprehensive seed data for testing payout functionality
- Include payout CSS in application stylesheet
- Document payout system implementation in AGENT.md
- Add payout feature to BACKLOG.md

This completes the full promoter payout system allowing event organizers
to request and track revenue payouts for completed events.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

app/assets/stylesheets/application.postcss.css

@@ -13,3 +13,4 @@
 
 /* Import pages */
 @import "pages/home";
+@import "pages/payouts";