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/i18n/translations.ts

@@ -632,6 +632,24 @@ export interface Translations {
     iconAltLabelDesc: string;
     socialLinkUrlDesc: string;
     staticPagesFieldDesc: string;
+    additionalPhones: string;
+    additionalPhonesDesc: string;
+    addPhone: string;
+    removePhone: string;
+    additionalEmails: string;
+    additionalEmailsDesc: string;
+    addEmail: string;
+    removeEmail: string;
+    footerColumns: string;
+    footerColumnsDesc: string;
+    footerColumnTitlePlaceholder: string;
+    footerLinkLabelPlaceholder: string;
+    footerLinkExistingPage: string;
+    footerLinkCustomUrl: string;
+    addColumn: string;
+    removeColumn: string;
+    addColumnLink: string;
+    removeColumnLink: string;
     sectionVisibleDesc: string;
     layoutStrategyLabel: string;
     layoutStrategyDesc: string;