feat(builder): implement visual homepage builder

New HomepageOverviewComponent (Tasks 1+8), mounted at the top of the
existing Homepage section page: completion ring, active/hidden section
counts, recommended next step, last-modified timestamp, and a 6-item
Homepage Health checklist (hero/categories/products/promotion/
newsletter/any-sections) - all derived from the real page.sections/
widgets data already in the facade, nothing fabricated.

Existing page-level drag-and-drop reordering (homepage-section's
CdkDragDrop over page.sections) was already implemented pre-Sprint 5 -
left as-is per "build on top of, do not replace."

Widgets section (Task 2) rewritten from a bare list into visual cards:
per-widget icon + humanized type label (hero/categories/product-
collection), a visible/hidden toggle and badge, up/down move buttons
(keyboard-accessible reorder within a section - see Known limitations
for why this replaces pointer drag for widgets specifically), duplicate,
and remove (with confirm). The existing per-type field editors (hero/
categories/product-collection) are unchanged; the raw-JSON fallback for
unknown widget types now sits behind a collapsed "Advanced settings"
disclosure instead of being the default view.

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

src/app/i18n/translations.ts

@@ -778,6 +778,28 @@ export interface Translations {
     brandSocialEmpty: string;
     brandAccentColor: string;
     brandBorderColor: string;
+    homepageOverviewTitle: string;
+    homepageOverviewSubtitle: string;
+    homepageOverviewComplete: string;
+    homepageActiveSections: string;
+    homepageDisabledSections: string;
+    homepageHealthHero: string;
+    homepageHealthCategories: string;
+    homepageHealthProducts: string;
+    homepageHealthPromotion: string;
+    homepageHealthNewsletter: string;
+    homepageHealthAnySections: string;
+    widgetTypeHero: string;
+    widgetTypeCategories: string;
+    widgetTypeProducts: string;
+    widgetHidden: string;
+    widgetVisible: string;
+    widgetMoveUp: string;
+    widgetMoveDown: string;
+    widgetDuplicate: string;
+    widgetRemove: string;
+    widgetRemoveConfirm: string;
+    widgetAdvancedSettings: string;
   };
   dashboard: {
     title: string;