Add per-event finance, event team permissions and public door sales state.

Event finance
- Finance tab on the event page: P&L summary with a revenue-to-result
  waterfall, costs and other income in one ledger, and the partner split
  with payouts. Lifecycle stepper (Selling, Adding costs, Ready to close,
  Finalized) with what is left to do; closing the books goes through a
  checklist dialog that freezes the numbers.
- Expense modal shows only the fields each calculation type needs, a live
  preview with the event's real counts, and a category suggested from the
  description. Date inputs follow the UI language.
- Global Finance page: profit per event with outliers clipped and labelled,
  and a "Ready to close" list of past events whose books are still open.
- Calculation service (integer PYG, basis points) with pinned regression
  scenarios; PYG formatting centralised in lib/money with locale-aware
  separators.

Event team permissions
- Per-event members with role presets and requireEventPermission; the
  header stat "Confirmed" is relabelled "Not checked in yet", which is
  what it counts.

Public sales state
- One sales state (online, door, sold out, ended, external, cancelled) for
  the event page, listings and JSON-LD, with the door price and tenders
  shown only while people can still pay at the door.

Frontend unit tests run with vitest (npm test in frontend/).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/lib/api/emails.ts

@@ -3,7 +3,9 @@ import type { EmailTemplate, EmailVariable, EmailLog, EmailStats, Pagination } f
 
 export const emailsApi = {
   // Templates
-  getTemplates: () => fetchApi<{ templates: EmailTemplate[] }>('/api/emails/templates'),
+  // Team members (non-admin) pass the event they email for, so the server can check their permission there.
+  getTemplates: (eventId?: string) =>
+    fetchApi<{ templates: EmailTemplate[] }>(`/api/emails/templates${eventId ? `?eventId=${encodeURIComponent(eventId)}` : ''}`),
 
   getTemplate: (id: string) => fetchApi<{ template: EmailTemplate }>(`/api/emails/templates/${id}`),
 
@@ -56,8 +58,8 @@ export const emailsApi = {
     templateSlug: string;
     variables?: Record<string, any>;
     locale?: string;
-  }) =>
-    fetchApi<{ subject: string; bodyHtml: string }>('/api/emails/preview', {
+  }, eventId?: string) =>
+    fetchApi<{ subject: string; bodyHtml: string }>(`/api/emails/preview${eventId ? `?eventId=${encodeURIComponent(eventId)}` : ''}`, {
       method: 'POST',
       body: JSON.stringify(data),
     }),