Restructure registration ticket into a two-tier card system

[maebeale]

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

• The registration ticket had accumulated several one-off colored callouts (event details, CE hours, W-9, invoice) that all competed for attention with no clear hierarchy.
• This restructures the ticket so the registrant can tell at a glance what they need to do versus what they can look up later.

How did you approach the change?

• Grouped the callouts into two tiers:
  • Before the event (action tier, amber) — things the registrant must do or decide: pay a balance, join online, read event details, choose CE hours.
  • For your records (reference tier, neutral grey) — documents to look up: invoice, W-9.
• Extracted a single reusable _ticket_card partial with exactly two variants (action / reference) so adding a new ticket section is one render against a fixed palette — no new accent colors.
• Shrunk the event image to an inline thumbnail beside the title to reclaim vertical space.

Rebase notes (onto current main)

• Folded in main's payment changes that landed since this branch started: the intends_to_pay? "Access granted — payment pending" chip (now inside the payment-due card) and the dollars_from_cents helper (replacing the local format("%.2f", …)).
• Main's admin-configured registration_ticket_callouts feature merged cleanly and renders below the two tiers. It keeps its own multi-color theme system, which is in tension with this PR's two-variant rule — flagged inline for a follow-up decision rather than redesigned here.

Anything else to add?

• The two-variant palette is deliberate — the partial doc comment forbids introducing a third accent color so the hierarchy stays legible.
• spec/system/event_registration_show_spec.rb passes (19 examples, 0 failures) including both main's callout tests and the new CE-hours / reference-tier tests.

🤖 Generated with Claude Code

[maebeale]

🤖 From Claude: Rebase note — main's admin-configured ticket callouts (#1740-era) auto-merged here and now render as standalone cards alongside the new two-tier system. They use their own multi-color callout.theme, which is intentionally at odds with this PR's "two variants only, no third accent color" _ticket_card rule. Left as-is to preserve the feature, but worth deciding whether callouts should eventually route through _ticket_card (action/reference) or stay a separate styled system.