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>

app/models/user.rb

@@ -31,6 +31,11 @@ class User < ApplicationRecord
   validates :first_name,  length: { minimum: 2, maximum: 50, allow_blank: true }
   validates :company_name, length: { minimum: 2, maximum: 100, allow_blank: true }
 
+  # Banking information validations
+  validates :iban, format: { with: /\A[A-Z]{2}[0-9]{2}[A-Z0-9]{4}[0-9]{7}([A-Z0-9]?){0,16}\z/, message: "must be a valid IBAN format" }, allow_blank: true
+  validates :bank_name, length: { minimum: 2, maximum: 100 }, allow_blank: true
+  validates :account_holder_name, length: { minimum: 2, maximum: 100 }, allow_blank: true
+
   # Onboarding methods
   def needs_onboarding?
     !onboarding_completed?
@@ -65,7 +70,17 @@ class User < ApplicationRecord
   end
 
   def can_receive_payouts?
-    stripe_connected_account_id.present? && stripe_connect_verified?
+    has_complete_banking_info?
+  end
+
+  # Banking information methods
+  def has_complete_banking_info?
+    iban.present? && bank_name.present? && account_holder_name.present?
+  end
+
+  def banking_info_summary
+    return "No banking information" unless has_complete_banking_info?
+    "#{account_holder_name} - #{bank_name} - #{iban}"
   end
   private