feat(builder): nav/menu link-to-page picker, page sync, download attr, box-model rollout

NavStylePanel (Navbar/Menu/Logo/Footer):
- LinkPicker: dropdown of the site's pages (read-only via usePages()) plus
  manual URL / #anchor / tel: / mailto: entry, wired into every link-href
  field (standalone Logo href, Navbar logoUrl, Navbar/Menu link items).
- "Sync links with Pages" button in the Links section: repopulates the
  links array from the current pages list (label = page name, href = '/'
  for the landing page else '/{slug}'), preserving any existing CTA link.
  Regression-fix vs the legacy GrapesJS builder, which had this.
- `download` checkbox per link (Navbar/Menu links, standalone Logo href)
  emits the `download` attribute on export for links to files.
- Links/Colors sections now gate on the component actually carrying a
  `links`/color prop, so Footer (no links array) no longer shows a dead
  "Add Link" editor.
- Box-model (Margin/Padding via SpacingControl, Border & Effects via
  BorderControl + box-shadow presets + opacity), AnimationControl, and
  VisibilityControl added for all four owned components, backed by new
  animation/animationDelay/hideOnDesktop/hideOnTablet/hideOnMobile props
  (with blank/default values in each component's .craft.props).

Tests: NavStylePanel.test.tsx (new, 17 tests: LinkPicker modes, sync
preserves CTA, download toggle, box-model/animation/visibility wiring) +
extended Navbar/Menu/Logo/Footer .toHtml.test.ts (download attribute,
craft.props defaults). Full suite: 683/683 passing. `npm run build` green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

craft/src/components/basic/Logo.tsx

@@ -12,11 +12,18 @@ interface LogoProps {
   imageSrc?: string;
   imageWidth?: string;
   href?: string;
+  /** Adds the `download` attribute to the exported anchor (F3: link to a file). */
+  download?: boolean;
   fontFamily?: string;
   fontSize?: string;
   fontWeight?: string;
   color?: string;
   style?: CSSProperties;
+  hideOnDesktop?: boolean;
+  hideOnTablet?: boolean;
+  hideOnMobile?: boolean;
+  animation?: string;
+  animationDelay?: string;
 }
 
 /* ---------- Component ---------- */
@@ -27,6 +34,7 @@ export const Logo: UserComponent<LogoProps> = ({
   imageSrc = '',
   imageWidth = '120px',
   href = '/',
+  download = false,
   fontFamily = 'Inter, sans-serif',
   fontSize = '20px',
   fontWeight = '700',
@@ -44,6 +52,7 @@ export const Logo: UserComponent<LogoProps> = ({
     <a
       ref={(ref: HTMLElement | null): void => { if (ref) connect(drag(ref)); }}
       href={href}
+      download={download || undefined}
       onClick={(e) => e.preventDefault()}
       style={{
         textDecoration: 'none',
@@ -87,7 +96,13 @@ Logo.craft = {
     fontSize: '20px',
     fontWeight: '700',
     color: undefined,
+    download: false,
     style: {},
+    hideOnDesktop: false,
+    hideOnTablet: false,
+    hideOnMobile: false,
+    animation: 'none',
+    animationDelay: '0',
   } as LogoProps,
   rules: {
     canDrag: () => true,
@@ -122,8 +137,9 @@ Logo.craft = {
     flexShrink: '0',
     ...props.style,
   });
+  const downloadAttr = props.download ? ' download' : '';
 
   return {
-    html: `<a href="${escapeAttr(safeUrl(href))}"${aStyle ? ` style="${aStyle}"` : ''}>${innerHtml}</a>`,
+    html: `<a href="${escapeAttr(safeUrl(href))}"${downloadAttr}${aStyle ? ` style="${aStyle}"` : ''}>${innerHtml}</a>`,
   };
 };