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>

db/migrate/20250916221454_create_payouts.rb

@@ -0,0 +1,19 @@
+class CreatePayouts < ActiveRecord::Migration[8.0]
+  def change
+    create_table :payouts do |t|
+      t.references :user, null: false, foreign_key: true
+      t.references :event, null: false, foreign_key: true
+      t.integer :amount_cents, null: false
+      t.integer :fee_cents, null: false, default: 0
+      t.integer :status, null: false, default: 0
+      t.string :stripe_payout_id
+      t.integer :total_orders_count, null: false, default: 0
+      t.integer :refunded_orders_count, null: false, default: 0
+
+      t.timestamps
+    end
+
+    add_index :payouts, :status
+    add_index :payouts, :stripe_payout_id, unique: true
+  end
+end