HOLD: Add admin CRUD for payments with filtering and manage registrants integration

[maebeale]

What is the goal of this PR and why is this important?

• Add full admin CRUD for payments, enabling tracking of financial transactions (Stripe, check, scholarship, purchase order, etc.) linked to payers, organizations, and event registrations
• Support filtering payments by payer, organization, event, and status for quick lookups
• Show payment status on the manage registrants page with links to filtered payment views

How did you approach the change?

Model & associations:

• Payment belongs_to :payer (Person), optional belongs_to :organization, has_many :event_registrations
• EventRegistration belongs_to :payment, optional: true (direct FK, not join table)
• Organization has_many :payments, dependent: :nullify
• Added normalizes on stripe fields to convert empty strings to nil
• search_by_params class method for filtering by status, payer_id, organization_id, event_id

Controller & views:

• Full CRUD with admin-only ActionPolicy authorization
• Index with remote-select search boxes for Payer, Organization, Event, and Status dropdown
• Form with remote-select for payer/organization and Stimulus controller for managing event registration associations
• Manage registrants view shows payment status badges linking to payments_path(payer_id: ...)

Migrations:

• Original payments table migration updated to include event_registrations.payment_id FK
• Separate migrations for payment_type column and organization_id reference
• Organization FK uses type: :integer to match organizations table PK type

Tests:

• Payment request spec: admin CRUD + filter tests (payer_id, organization_id, event_id, status) + auth tests
• Events request spec: manage page tests for paid/free events and payment status display
• Model spec, factory with :with_organization trait
• Page bg_class alignment spec updated

UI Testing Checklist

• Visit /payments as admin — verify index renders with search filters
• Create a new payment with payer and organization
• Edit a payment, change organization — verify it saves
• Create a payment without Stripe fields (payment_type: "other") — should work without validation errors
• Filter by payer, organization, event, status on index
• Visit manage registrants for a paid event — verify payment status badges link to filtered payments
• Visit manage registrants for a free event — verify no payment column

Anything else to add?

• Seeds include realistic payment data with most payments succeeded and a few in other statuses, some bundling multiple event registrations under a single payment
• Event model now includes RemoteSearchable to support the event filter on payments index

🤖 Generated with Claude Code

[jmilljr24]

I think we should have a full chat about payments as well as look at using the pay gem before we get too deep in this.