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/20250916221454_create_payouts.rb

@@ -11,10 +11,17 @@ class CreatePayouts < ActiveRecord::Migration[8.0]
       t.references :user, null: false, foreign_key: false
       t.references :event, null: false, foreign_key: false
 
+      # Manual processing fields
+      t.references :processed_by, null: true, foreign_key: { to_table: :users }
+      t.datetime :processed_at
+      t.text :rejection_reason
+      t.string :bank_transfer_reference
+
       t.timestamps
     end
 
     add_index :payouts, :status
     add_index :payouts, :stripe_payout_id, unique: true
+    add_index :payouts, [:event_id, :status]
   end
 end