fix(project-editor): validate footer payment/social links, add footer logo picker

- header-section: raw checkboxes -> app-toggle, wrap in SectionCard
- footer-section: replace unvalidated pipe-delimited textareas for payment
  icons/social links with KeyValueEditor + MediaPickerComponent, add missing
  footer logo picker, validate social link URLs (http/https), wrap in SectionCard
- i18n: add footer logo / key-value-editor labels and URL validation message

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

src/app/i18n/translations.ts

@@ -450,6 +450,15 @@ export interface Translations {
     copyright: string;
     paymentIcons: string;
     socialLinks: string;
+    footerLogo: string;
+    addPaymentIcon: string;
+    removePaymentIcon: string;
+    iconAltLabel: string;
+    addSocialLink: string;
+    removeSocialLink: string;
+    socialLinkLabel: string;
+    socialLinkUrl: string;
+    invalidUrl: string;
     createPage: string;
     deletePage: string;
     pageId: string;
@@ -588,6 +597,9 @@ export interface Translations {
     copyrightDesc: string;
     paymentIconsDesc: string;
     socialLinksDesc: string;
+    footerLogoDesc: string;
+    iconAltLabelDesc: string;
+    socialLinkUrlDesc: string;
     staticPagesFieldDesc: string;
     sectionVisibleDesc: string;
     layoutStrategyLabel: string;