HOLD: Uniform public form lanes: /events/:id/forms/:role with standalone scholarship/CE/general

[maebeale]

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

• Give every public event form a single, uniform, shareable URL: /events/:id/forms/<role>/new. The lane is visible in the path, so each entry point is unambiguous (clean analytics) and links are easy to share.
• Let scholarship and CE forms be accessed directly, not only bundled into a registration, and add a general public form lane.

URL scheme

Lane	URL	Renders / does
registration	/events/:id/forms/registration/new	registration form → creates a registration
scholarship	/events/:id/forms/scholarship/new	registration + scholarship (primary scholarship link)
scholarship_questions	/events/:id/forms/scholarship_questions/new?reg=SLUG	scholarship questions only → attaches to an existing registration, sets scholarship_requested
ce_questions	/events/:id/forms/ce_questions/new?reg=SLUG	CE questions only → attaches to an existing registration, sets ce_credit_requested
general	/events/:id/forms/general/new	general form → recorded as a FormSubmission
bulk_payment	/events/:id/forms/bulk_payment/new	main's BulkPaymentsController (uniform URL, own controller)

How

• One param'd route set (forms/:form_role new/create/show) → Events::PublicFormsController. A LANES config maps each lane to its form(s), heading, and behavior mode (:register / :addon / :submission).
• :addon lanes (scholarship_questions, ce_questions) resolve the existing registration by slug (?reg=) or the signed-in person's active registration; no registration → redirect with a "register first" notice.
• Bulk payment is mounted at the uniform forms/bulk_payment path but still routes to its own shipped controller — no change to that flow.
• EventForm::ROLES gains general; route helpers are now new_event_form_path(event, role) / event_form_path(event, role); all call sites + the admin Form-actions menu updated.

Verification

• ai/lint clean. Green: public_forms routing/system/request, bulk_payments, events, event_registrations, scholarships, event/event_form models, page_bg view spec, events_show.

🤖 Generated with Claude Code

[maebeale]

🤖 From Claude: form_variant is whitelisted against VARIANTS and falls back to "registration", so an unknown variant in the URL degrades to the default flow rather than blowing up the path helpers below.

[maebeale]

🤖 From Claude: Scholarship default differs by variant: the scholarship_form flow opts in unless scholarship_requested=false, while other flows opt in only when explicitly =true. This preserves the existing query-param behavior for the registration flow.

[maebeale]

🤖 From Claude: The registrant_registration resource stays separate from the three new public *_form resources — the routing spec asserts POST /events/:id/registrations still hits events/registrations#create and does not collide.

[maebeale]

🤖 From Claude: Kept main's dedicated bulk_payment resource (→ Events::BulkPaymentsController, the real multi-attendee flow) alongside the role loop. The loop also generates a bulk_payment_form lane through public_forms, but that's a registration-form-backed placeholder at a different path — the two coexist and the admin menu surfaces the real one.