feat: replace Stripe Global Payouts with manual bank transfer system for France compliance

- Replace Stripe automatic payouts with manual admin-processed bank transfers
- Add banking information fields (IBAN, bank name, account holder) to User model
- Implement manual payout workflow: pending → approved → processing → completed
- Add comprehensive admin interface for payout review and processing
- Update Payout model with manual processing fields and workflow methods
- Add transfer reference tracking and rejection/failure handling
- Consolidate all migration fragments into clean "create" migrations
- Add comprehensive documentation for manual payout workflow
- Fix Event payout_status enum definition and database column issues

This addresses France's lack of Stripe Global Payouts support by implementing
a complete manual bank transfer workflow while maintaining audit trails and
proper admin controls.

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

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

db/migrate/20250816145933_devise_create_users.rb

@@ -55,6 +55,11 @@ class DeviseCreateUsers < ActiveRecord::Migration[8.0]
       # Link user to Stripe account for promoter payout
       t.string :stripe_connected_account_id
 
+      # Banking information for manual payouts
+      t.string :iban
+      t.string :bank_name
+      t.string :account_holder_name
+
       t.timestamps null: false
     end