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/shared/models/config/company.model.ts

@@ -11,6 +11,10 @@ export interface CompanyContactConfig {
   phone?: string;
   telegram?: string;
   website?: string;
+  /** Extra phone numbers, e.g. for country-specific support lines. `phone` stays the primary/default one. */
+  additionalPhones?: string[];
+  /** Extra email addresses. `email` stays the primary/default one. */
+  additionalEmails?: string[];
 }
 
 export interface CompanyConfig {

src/app/shared/models/config/footer-config.model.ts

@@ -14,11 +14,29 @@ export interface FooterSocialLinkConfig {
   icon?: string;
 }
 
+export interface FooterLinkConfig {
+  id: string;
+  label: string;
+  /** Key of an existing static page (features/content-management ContentPage.id) - preferred over a raw URL so the link stays correct if the page's route ever changes. */
+  pageKey?: string;
+  /** Used only when pageKey is empty - an external or custom URL. */
+  url?: string;
+}
+
+export interface FooterColumnConfig {
+  id: string;
+  title: string;
+  links: FooterLinkConfig[];
+}
+
 export interface FooterConfig {
   logoUrl?: string;
   paymentIcons?: FooterPaymentIconConfig[];
   copyrightText?: string | LocalizedTextContent;
+  /** @deprecated superseded by `columns` - kept so already-saved configs still resolve until re-saved through the Footer Builder. */
   legalPageKeys?: string[];
+  /** @deprecated superseded by `columns` - kept so already-saved configs still resolve until re-saved through the Footer Builder. */
   staticPageKeys?: string[];
+  columns?: FooterColumnConfig[];
   socialLinks?: FooterSocialLinkConfig[];
 }