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>

config/routes.rb

@@ -2,7 +2,12 @@ Rails.application.routes.draw do
   namespace :admin do
     resources :payouts, only: [ :index, :show ] do
       member do
-        post :process
+        post :process          # Legacy route
+        post :approve
+        post :reject
+        post :mark_processing
+        post :mark_completed
+        post :mark_failed
       end
     end
   end