feat: Implement promoter payout system for event revenue processing

- Add Payout model with associations to User and Event
- Create payout requests for completed events with proper earnings calculation
- Exclude refunded tickets from payout calculations
- Add promoter dashboard views for managing payouts
- Implement admin interface for processing payouts
- Integrate with Stripe for actual payment processing
- Add comprehensive tests for payout functionality

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

test/fixtures/payouts.yml

@@ -0,0 +1,15 @@
+# Read about fixtures at https://api.rubyonrails.org/classes/ActiveRecord/FixtureSet.html
+
+one:
+  user: one
+  event: one
+  amount_cents: 10000
+  fee_cents: 1000
+  status: pending
+
+two:
+  user: two
+  event: two
+  amount_cents: 20000
+  fee_cents: 2000
+  status: completed