feat(builder): visual footer builder with drag-and-drop columns

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

P0 user feedback: footer static pages were comma-separated text; no way to add extra phones/emails for different countries.

- New FooterColumnConfig/FooterLinkConfig model (footer-config.model.ts): columns of links, each link pointing at an existing static page (resolved by key, so it survives route renames) or a custom URL
- Footer Builder UI: add/remove columns and links, per-link toggle between 'existing page' (dropdown of real static pages) and 'custom URL', drag-and-drop reordering of both columns and links via @angular/cdk/drag-drop (same primitive already used by the homepage section builder)
- Wired FooterResolverService (the service the real storefront footer actually renders through) to read footer.columns as the primary source when present - without this the builder would have saved data nobody ever displayed. Falls back to the existing legacy static-page auto-grouping when no columns are configured, so existing sites are unaffected
- CompanyContactConfig gains additionalPhones/additionalEmails (primary phone/email field unchanged) with add/remove UI for country-specific support lines
- Old comma-separated staticPageKeys input removed from the UI; field kept on the model as deprecated/read-compat only
- New builder.* i18n keys (en/ru/hy); fixed an accidental duplicate-key collision with pre-existing navigation-section addLink/removeLink keys during the rename pass
- Verified in browser: added column, added link, switched link source page->custom, added phone number - all reactive and error-free

src/app/core/config/footer-resolver.service.ts

@@ -3,6 +3,7 @@ import { map, Observable } from 'rxjs';
 import { ConfigService } from './config.service';
 import {
   BootstrapConfig,
+  FooterColumnConfig,
   FooterConfig,
   FooterNavigationGroupConfig,
   FooterNavigationItemConfig,
@@ -63,6 +64,20 @@ export class FooterResolverService {
   private resolveFooterGroups(bootstrap: BootstrapConfig): FooterResolvedGroup[] {
     const footer = bootstrap.navigation?.footer ?? [];
     const lang = this.languageService.currentLanguage();
+
+    // Footer Builder columns (admin/edit/footer) take priority over both the
+    // legacy grouped-navigation config and the auto-grouped-by-static-page
+    // fallback below - once a merchant builds columns, that's their footer.
+    if (bootstrap.footer?.columns?.length) {
+      const groups = this.resolveGroupsFromColumns(bootstrap.footer.columns, bootstrap, lang)
+        .filter(group => group.items.length > 0);
+      const social = this.resolveSocialGroup(bootstrap.footer);
+      if (social) {
+        groups.push(social);
+      }
+      return groups;
+    }
+
     const contentPages = this.resolveBootstrapStaticPages(bootstrap, lang);
 
     if (this.isGroupedFooter(footer)) {
@@ -118,13 +133,9 @@ export class FooterResolverService {
       groups.get(groupId)!.items.push({ id: resolved.id, label: resolved.title, route: resolved.route });
     }
 
-    const socialLinks = bootstrap.footer?.socialLinks ?? [];
-    if (socialLinks.length > 0) {
-      groups.set('footer-group-social', {
-        id: 'footer-group-social',
-        title: 'Social',
-        items: socialLinks.map(link => ({ id: link.id, label: link.label, route: link.url, external: true }))
-      });
+    const social = this.resolveSocialGroup(bootstrap.footer);
+    if (social) {
+      groups.set(social.id, social);
     }
 
     return [...groups.values()].map(group => ({
@@ -133,6 +144,41 @@ export class FooterResolverService {
     }));
   }
 
+  private resolveSocialGroup(footerConfig: FooterConfig | undefined): FooterResolvedGroup | null {
+    const socialLinks = footerConfig?.socialLinks ?? [];
+    if (socialLinks.length === 0) {
+      return null;
+    }
+    return {
+      id: 'footer-group-social',
+      title: 'Social',
+      items: socialLinks.map(link => ({ id: link.id, label: link.label, route: link.url, external: true }))
+    };
+  }
+
+  /** Footer Builder columns -> resolved groups. Page-linked entries resolve through StaticPageResolverService (so a page's route stays correct even if it changes); custom URLs pass through as external links. */
+  private resolveGroupsFromColumns(columns: FooterColumnConfig[], bootstrap: BootstrapConfig, lang: string): FooterResolvedGroup[] {
+    return columns.map((column, index) => ({
+      id: column.id || `footer-group-${index}`,
+      title: column.title,
+      items: column.links
+        .map((link): FooterResolvedItem | null => {
+          if (link.pageKey) {
+            const staticPage = this.staticPageResolver.resolveByKeyFromBootstrap(bootstrap, link.pageKey, lang);
+            if (!staticPage) {
+              return null;
+            }
+            return { id: link.id, label: link.label || staticPage.title, route: staticPage.route };
+          }
+          if (!link.url) {
+            return null;
+          }
+          return { id: link.id, label: link.label || link.url, route: link.url, external: true };
+        })
+        .filter((item): item is FooterResolvedItem => item !== null),
+    }));
+  }
+
   private resolveGroupFromConfig(
     group: FooterNavigationGroupConfig,
     bootstrap: BootstrapConfig,