feat(admin): implement analytics and monitoring center

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

- Business Dashboard: revenue/orders/customers/AOV/top products/low stock/recent activity/warnings/completion% (Overview tab)
- Marketplace Health: real completion checks (images, SEO, categories, reviews, orders, translations, homepage, backend, performance) with clickable recommendations
- Product Analytics: top selling/most reviewed/worst rated/hidden/archived counts; top-viewed honestly marked Unknown (no view tracking exists)
- Customer Analytics: new/returning customers, average spend, retention - derived from real order data
- Search & Traffic tabs: honest 'Unknown - available after backend integration' placeholders, no fabricated numbers
- Recommendations engine: actionable cards (missing images/SEO/category, empty categories, incomplete homepage, unpublished static pages) linking to the relevant admin page
- System Monitoring: added real draft/publish/sync/backend-connectivity state from AdminDashboardFacade
- CSV export extended to top products and health checks; added print action
- New adminAnalytics.* and adminMarketplaceHealth.* i18n namespaces (en/ru/hy), no raw i18n keys
- Reused existing shared UI (app-table/app-badge/app-skeleton/app-empty-state) and content-health-widget completion-meter pattern - no new backend APIs, no storage changes

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

@@ -1,14 +1,57 @@
 .admin-analytics-page { display: grid; gap: 16px; padding: 16px; max-width: 1100px; margin: 0 auto; }
 .toolbar { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 10px; }
+.toolbar-actions { display: flex; gap: 8px; }
 .ranges { display: flex; gap: 6px; }
+
+.tabs { display: flex; flex-wrap: wrap; gap: 4px; border-bottom: 1px solid var(--border-color, #d3dad9); }
+.tab {
+  border: none;
+  background: transparent;
+  padding: 10px 14px;
+  font-size: 0.85rem;
+  font-weight: 600;
+  color: var(--text-secondary, #6b7280);
+  cursor: pointer;
+  border-bottom: 2px solid transparent;
+}
+.tab:hover { color: var(--text-primary, #1e3c38); }
+.tab:focus-visible { outline: 2px solid var(--color-primary, #2f8f5b); outline-offset: 2px; }
+.tab--active { color: var(--color-primary, #2f8f5b); border-bottom-color: var(--color-primary, #2f8f5b); }
+
+.panel { display: grid; gap: 16px; }
+
 .summary-grid { display: grid; grid-template-columns: repeat(6, minmax(0, 1fr)); gap: 10px; }
 .summary-card { border: 1px solid var(--border-color, #d3dad9); border-radius: 12px; padding: 12px; display: grid; gap: 4px; background: #fff; }
 .summary-card span { font-size: 0.75rem; color: var(--text-secondary, #6b7280); }
 .summary-card strong { font-size: 1.1rem; }
+
 .card { display: grid; gap: 12px; padding: 16px; border: 1px solid var(--border-color, #d3dad9); border-radius: 16px; background: #fff; }
+.card-head { display: flex; justify-content: space-between; align-items: center; }
 .card h2 { margin: 0; font-size: 1.1rem; }
 .chart { display: flex; align-items: flex-end; gap: 3px; height: 140px; }
 .chart .bar { flex: 1; background: var(--color-primary, #2f8f5b); border-radius: 3px 3px 0 0; min-height: 2px; }
 .pending-section p { display: flex; align-items: center; gap: 8px; margin: 0; color: var(--text-secondary, #6b7280); }
-@media (max-width: 900px) { .summary-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
 .skeleton-rows { display: grid; gap: 8px; }
+
+.grid-2 { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; }
+
+.activity-list, .warning-list, .recommendation-list, .health-checks { list-style: none; margin: 0; padding: 0; display: grid; gap: 8px; font-size: 0.85rem; }
+.activity-list li { display: flex; justify-content: space-between; gap: 8px; }
+.warning-list li, .recommendation-list li, .health-checks li { display: flex; align-items: center; gap: 10px; }
+.recommendation-list a, .health-checks a { color: var(--text-primary, #1e3c38); text-decoration: underline; }
+.recommendation-list a:focus-visible, .health-checks a:focus-visible { outline: 2px solid var(--color-primary, #2f8f5b); outline-offset: 2px; }
+.muted { color: var(--text-secondary, #6b7280); font-size: 0.8rem; }
+
+.health-widget__bar { height: 8px; border-radius: 999px; background: var(--surface-muted, #eef2f0); overflow: hidden; }
+.health-widget__bar-fill { height: 100%; background: var(--brand-primary, #1e8a6e); transition: width 0.3s ease; }
+.health-percent { margin: 0; font-size: 0.85rem; color: var(--text-secondary, #6b7280); }
+
+@media (max-width: 900px) {
+  .summary-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
+  .grid-2 { grid-template-columns: 1fr; }
+}
+
+@media (max-width: 560px) {
+  .summary-grid { grid-template-columns: 1fr; }
+  .tabs { overflow-x: auto; flex-wrap: nowrap; }
+}