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/20250823145902_create_events.rb

@@ -23,7 +23,7 @@ class CreateEvents < ActiveRecord::Migration[8.0]
       t.boolean :allow_booking_during_event, default: false, null: false
 
       # Payout fields
-      t.integer :payout_status
+      t.integer :payout_status, default: 0, null: false
       t.datetime :payout_requested_at
 
       t.timestamps