feat: Phase 2 frontend - Notification Center (mock-gateway backed)

New features/admin/notifications module against
docs/backend/PHASE-2-ORDERS-NOTIFICATIONS-CONTRACT.md §6: model, gateway
interface + local mock (derives notifications from the existing real
ADMIN_ORDERS_GATEWAY so the shape is genuine), facade, page (unread
filter, event-type filter, mark-read/mark-all-read). New /backoffice/
notifications route + nav entry (nav i18n key added in all 3 languages;
page body copy is plain English - see scope note below).

Existing AdminOrder model/facade/mock-gateway were already solid and
real (just gained a DI token this session) - Order/OrderLine/Fulfillment
canonical-model rework from the Phase 2 contract is deferred; today's
AdminOrder shape is close enough to build the Notification Center against
without a disruptive rewrite of an already-working admin surface.

Scope note (applies going forward for this "do all phases" push): new
page body text uses plain English instead of the full TranslatePipe/
i18n-key system. Multiplying every new string across en/ru/hy + the
Translations type for every phase isn't sustainable at this pace: nav
labels (few, highly visible) still get real i18n keys; page content
does not. Flagged for a follow-up i18n pass before any of this ships.

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

src/app/features/admin/notifications/facade/admin-notifications.facade.ts

@@ -0,0 +1,36 @@
+import { Injectable, computed, inject, signal } from '@angular/core';
+import { take } from 'rxjs/operators';
+import { AdminNotification, AdminNotificationFilters } from '../models/admin-notification.model';
+import { ADMIN_NOTIFICATIONS_GATEWAY } from '../services/admin-notifications-gateway.token';
+
+@Injectable({ providedIn: 'root' })
+export class AdminNotificationsFacade {
+  private readonly gateway = inject(ADMIN_NOTIFICATIONS_GATEWAY);
+
+  readonly filters = signal<AdminNotificationFilters>({ marketplaceId: '', eventType: 'all', unreadOnly: false });
+  readonly notifications = signal<AdminNotification[]>([]);
+  readonly loading = signal(false);
+
+  readonly unreadCount = computed(() => this.notifications().filter(n => !n.read).length);
+
+  load(): void {
+    this.loading.set(true);
+    this.gateway.loadNotifications(this.filters()).pipe(take(1)).subscribe(items => {
+      this.notifications.set(items);
+      this.loading.set(false);
+    });
+  }
+
+  updateFilters(patch: Partial<AdminNotificationFilters>): void {
+    this.filters.update(current => ({ ...current, ...patch }));
+    this.load();
+  }
+
+  markRead(id: string): void {
+    this.gateway.markRead(id).pipe(take(1)).subscribe(() => this.load());
+  }
+
+  markAllRead(): void {
+    this.gateway.markAllRead().pipe(take(1)).subscribe(() => this.load());
+  }
+}

src/app/features/admin/notifications/models/admin-notification.model.ts

@@ -0,0 +1,22 @@
+/** Per docs/backend/PHASE-2-ORDERS-NOTIFICATIONS-CONTRACT.md §6. */
+export type AdminNotificationSeverity = 'info' | 'warning' | 'critical';
+export type AdminNotificationEntityType = 'order' | 'payment' | 'offer' | 'connector' | 'refund';
+
+export interface AdminNotification {
+  id: string;
+  marketplaceId: string;
+  entityType: AdminNotificationEntityType;
+  entityId: string;
+  severity: AdminNotificationSeverity;
+  eventType: string;
+  title: string;
+  read: boolean;
+  deepLink: string[];
+  createdAt: string;
+}
+
+export interface AdminNotificationFilters {
+  marketplaceId: string;
+  eventType: string;
+  unreadOnly: boolean;
+}

src/app/features/admin/notifications/pages/admin-notifications-page.component.html

@@ -0,0 +1,38 @@
+<div class="notifications-page">
+  <header class="notifications-page__header">
+    <div>
+      <h1>Notifications</h1>
+      <p>Mock-gateway backed until docs/backend/PHASE-2-ORDERS-NOTIFICATIONS-CONTRACT.md ships.</p>
+    </div>
+    <app-button variant="secondary" (click)="facade.markAllRead()">Mark all read</app-button>
+  </header>
+
+  <div class="notifications-page__filters">
+    <label>
+      <input type="checkbox" [ngModel]="facade.filters().unreadOnly" (ngModelChange)="facade.updateFilters({ unreadOnly: $event })" />
+      Unread only
+    </label>
+    <select [ngModel]="facade.filters().eventType" (ngModelChange)="facade.updateFilters({ eventType: $event })">
+      @for (type of eventTypes; track type) {
+        <option [value]="type">{{ type }}</option>
+      }
+    </select>
+  </div>
+
+  @if (facade.notifications().length === 0 && !facade.loading()) {
+    <app-empty-state title="No notifications" description="Nothing matches the current filter." />
+  } @else {
+    <ul class="notifications-page__list">
+      @for (n of facade.notifications(); track n.id) {
+        <li class="notifications-page__item" [class.notifications-page__item--unread]="!n.read">
+          <app-badge [variant]="n.severity === 'critical' ? 'danger' : n.severity === 'warning' ? 'warning' : 'info'">{{ n.severity }}</app-badge>
+          <a [routerLink]="['/', currentLang(), 'backoffice', ...n.deepLink]">{{ n.title }}</a>
+          <span class="notifications-page__time">{{ n.createdAt | date: 'short' }}</span>
+          @if (!n.read) {
+            <button type="button" (click)="facade.markRead(n.id)">Mark read</button>
+          }
+        </li>
+      }
+    </ul>
+  }
+</div>

src/app/features/admin/notifications/pages/admin-notifications-page.component.scss

@@ -0,0 +1,46 @@
+.notifications-page {
+  display: flex;
+  flex-direction: column;
+  gap: 16px;
+
+  &__header {
+    display: flex;
+    justify-content: space-between;
+    align-items: flex-start;
+  }
+
+  &__filters {
+    display: flex;
+    gap: 16px;
+    align-items: center;
+  }
+
+  &__list {
+    list-style: none;
+    margin: 0;
+    padding: 0;
+    display: flex;
+    flex-direction: column;
+    gap: 8px;
+  }
+
+  &__item {
+    display: flex;
+    align-items: center;
+    gap: 12px;
+    padding: 12px;
+    border: 1px solid var(--border-color);
+    border-radius: var(--radius-md);
+
+    &--unread {
+      background: var(--bg-secondary);
+      font-weight: var(--font-weight-bold, 700);
+    }
+  }
+
+  &__time {
+    margin-left: auto;
+    color: var(--text-secondary);
+    font-weight: normal;
+  }
+}

src/app/features/admin/notifications/pages/admin-notifications-page.component.ts

@@ -0,0 +1,29 @@
+import { ChangeDetectionStrategy, Component, inject } from '@angular/core';
+import { CommonModule } from '@angular/common';
+import { FormsModule } from '@angular/forms';
+import { RouterLink } from '@angular/router';
+import { AdminNotificationsFacade } from '../facade/admin-notifications.facade';
+import { LanguageService } from '../../../../services/language.service';
+import { BadgeComponent } from '../../../../shared/ui/badge/badge.component';
+import { ButtonComponent } from '../../../../shared/ui/button/button.component';
+import { EmptyStateComponent } from '../../../../shared/ui/empty-state/empty-state.component';
+
+@Component({
+  selector: 'app-admin-notifications-page',
+  standalone: true,
+  imports: [CommonModule, FormsModule, RouterLink, BadgeComponent, ButtonComponent, EmptyStateComponent],
+  templateUrl: './admin-notifications-page.component.html',
+  styleUrls: ['./admin-notifications-page.component.scss'],
+  changeDetection: ChangeDetectionStrategy.OnPush
+})
+export class AdminNotificationsPageComponent {
+  readonly facade = inject(AdminNotificationsFacade);
+  private readonly languageService = inject(LanguageService);
+  readonly currentLang = this.languageService.currentLanguage;
+
+  readonly eventTypes = ['all', 'order.created', 'order.paid'] as const;
+
+  constructor() {
+    this.facade.load();
+  }
+}

src/app/features/admin/notifications/services/admin-notifications-gateway.interface.ts

@@ -0,0 +1,8 @@
+import { Observable } from 'rxjs';
+import { AdminNotification, AdminNotificationFilters } from '../models/admin-notification.model';
+
+export interface AdminNotificationsGateway {
+  loadNotifications(filters: AdminNotificationFilters): Observable<AdminNotification[]>;
+  markRead(id: string): Observable<void>;
+  markAllRead(): Observable<void>;
+}

src/app/features/admin/notifications/services/admin-notifications-gateway.token.ts

@@ -0,0 +1,9 @@
+import { InjectionToken, inject } from '@angular/core';
+import { AdminNotificationsGateway } from './admin-notifications-gateway.interface';
+import { AdminNotificationsLocalGateway } from './admin-notifications-local.gateway';
+
+/** Swap point for docs/backend/PHASE-2-ORDERS-NOTIFICATIONS-CONTRACT.md §6. */
+export const ADMIN_NOTIFICATIONS_GATEWAY = new InjectionToken<AdminNotificationsGateway>('ADMIN_NOTIFICATIONS_GATEWAY', {
+  providedIn: 'root',
+  factory: () => inject(AdminNotificationsLocalGateway),
+});

src/app/features/admin/notifications/services/admin-notifications-local.gateway.ts

@@ -0,0 +1,50 @@
+import { Injectable, inject } from '@angular/core';
+import { Observable, map, of } from 'rxjs';
+import { AdminNotification, AdminNotificationFilters } from '../models/admin-notification.model';
+import { AdminNotificationsGateway } from './admin-notifications-gateway.interface';
+import { ADMIN_ORDERS_GATEWAY } from '../../orders/services/admin-orders-gateway.token';
+
+/**
+ * Derives notifications from the existing (mock) Orders gateway so the shape
+ * is real even before a platform event bus exists. Once
+ * docs/backend/PHASE-2-ORDERS-NOTIFICATIONS-CONTRACT.md §6 ships, swap the
+ * token - no caller changes needed.
+ */
+@Injectable({ providedIn: 'root' })
+export class AdminNotificationsLocalGateway implements AdminNotificationsGateway {
+  private readonly ordersGateway = inject(ADMIN_ORDERS_GATEWAY);
+  private readonly readIds = new Set<string>();
+
+  loadNotifications(filters: AdminNotificationFilters): Observable<AdminNotification[]> {
+    return this.ordersGateway.loadOrders({ search: '', status: 'all', page: 1, pageSize: 20 }).pipe(
+      map(result => result.items
+        .map((order): AdminNotification => ({
+          id: `notif_${order.id}`,
+          marketplaceId: 'default',
+          entityType: 'order',
+          entityId: order.id,
+          severity: order.status === 'cancelled' ? 'warning' : 'info',
+          eventType: order.payment.status === 'paid' ? 'order.paid' : 'order.created',
+          title: `Order ${order.orderNumber} - ${order.payment.status === 'paid' ? 'paid' : 'created'}`,
+          read: this.readIds.has(order.id),
+          deepLink: ['orders', order.id],
+          createdAt: order.createdAt,
+        }))
+        .filter(n => !filters.unreadOnly || !n.read)
+        .filter(n => !filters.eventType || filters.eventType === 'all' || n.eventType === filters.eventType)
+      )
+    );
+  }
+
+  markRead(id: string): Observable<void> {
+    const orderId = id.replace(/^notif_/, '');
+    this.readIds.add(orderId);
+    return of(void 0);
+  }
+
+  markAllRead(): Observable<void> {
+    return this.loadNotifications({ marketplaceId: '', eventType: '', unreadOnly: false }).pipe(
+      map(items => { items.forEach(n => this.readIds.add(n.entityId)); })
+    );
+  }
+}

src/app/features/admin/shell/admin-nav.model.ts

@@ -38,6 +38,7 @@ export const ADMIN_NAV_PRIMARY: AdminNavEntry[] = [
   { type: 'link', id: 'customers', icon: 'user', labelKey: 'adminShell.nav.customers', path: ['customers'] },
   { type: 'link', id: 'transactions', icon: 'creditCard', labelKey: 'adminShell.nav.transactions', path: ['transactions'] },
   { type: 'link', id: 'moderation', icon: 'star', labelKey: 'adminShell.nav.moderation', path: ['moderation'] },
+  { type: 'link', id: 'notifications', icon: 'bell', labelKey: 'adminShell.nav.notifications', path: ['notifications'] },
   { type: 'link', id: 'reports', icon: 'chartBar', labelKey: 'adminShell.nav.reports', path: ['reports'] },
   { type: 'group', labelKey: 'adminShell.nav.partnersGroup' },
   { type: 'link', id: 'seller-management', icon: 'store', labelKey: 'adminShell.nav.sellerManagement', path: ['partners', 'seller-management'] },