feat: Phase 7 frontend - Refund/Reconciliation core + Payments & Finance section

New core/finance (Refund/ReconciliationRecord/Settlement models + gateway/
token, mock backed, seeded empty) and features/admin/finance (facade +
page: reconciliation queue with resolve action, settlements placeholder).
New /backoffice/finance route + nav entry, nav i18n key in all 3 languages.
Against docs/backend/PHASE-7-PAYMENTS-RECONCILIATION-CONTRACT.md.

Note: does not wire AdminOrdersLocalGateway's existing mock
requestRefund(id) method into this new Refund flow yet - that's a small
follow-up once Phase 2's real Order backend exists to refund against.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/app/i18n/en.ts

@@ -2061,6 +2061,7 @@ export const en: Translations = {
       moderation: 'Reviews & Moderation',
       notifications: 'Notifications',
       integrations: 'Integrations',
+      finance: 'Payments & Finance',
       reviews: 'Reviews',
       reports: 'Reports',
       partnersGroup: 'Partners',

src/app/i18n/hy.ts

@@ -2055,6 +2055,7 @@ export const hy: Translations = {
       moderation: 'Կարծիքներ և մոդերացիա',
       notifications: 'Ծանուցումներ',
       integrations: 'Ինտեգրումներ',
+      finance: 'Վճարումներ և ֆինանսներ',
       transactions: 'Գործարքներ',
       reviews: 'Կարծիքներ',
       reports: 'Հաշվետվություններ',

src/app/i18n/ru.ts

@@ -2055,6 +2055,7 @@ export const ru: Translations = {
       moderation: 'Отзывы и модерация',
       notifications: 'Уведомления',
       integrations: 'Интеграции',
+      finance: 'Платежи и финансы',
       transactions: 'Транзакции',
       reviews: 'Отзывы',
       reports: 'Отчёты',

src/app/i18n/translations.ts

@@ -2070,6 +2070,7 @@ export interface Translations {
       moderation: string;
       notifications: string;
       integrations: string;
+      finance: string;
       reports: string;
       partnersGroup: string;
       sellerManagement: string;