feat: close stub-page gaps - profile login/logout, admin Reports/Settings, Help/Docs links

Sprint A: storefront header profile control (login/logout only, no menu),
wired to existing customer Telegram auth (AuthService).

Sprint B: backoffice/reports page, reuses AdminAnalyticsFacade (Sales,
Top Products, Marketplace Health cards + CSV export).

Sprint C: backoffice/settings page, admin UI density preference
(comfortable/compact), localStorage-persisted, applied to app-table
across all admin list pages.

Sprint D: admin bottom-nav Help -> mailto using existing supportEmail,
Documentation -> external link via new TenantConfig.documentationUrl.
AdminNavLink gains externalHref for non-routerLink nav entries.

Docs: docs/GLOBAL-SPRINT-PLAN.md tracks the full sprint breakdown.
docs/COMING-SOON-AUDIT.md removed, folded into docs/KNOWN-ISSUES.md.
docs/BACKEND.md updated with the new documentationUrl bootstrap field.

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

src/app/shared/ui/table/table.component.scss

@@ -50,3 +50,9 @@ app-table {
     background: var(--bg-secondary, #f4f4f5);
   }
 }
+
+.admin-density-compact .app-table {
+  th, td {
+    padding: var(--space-xs, 0.25rem) var(--space-md, 1rem);
+  }
+}