feat(builder): surface hidden section/pricing/social props + box-model rollout

SectionTypePanel (Accordion/Tabs/Testimonials/Countdown/NumberCounter/
CTASection/CallToAction/FeaturesGrid), PricingStylePanel, and
SocialStylePanel all gain a Spacing & Border section (margin/padding
per-side, border, box-shadow, opacity), an Animation section, and a
Visibility section, wired to the shared SpacingControl/BorderControl/
AnimationControl/VisibilityControl.

PricingTable's per-card colors (cardBg/textColor/subColor/featColor/
checkColor/btnBg/btnColor) were previously hard-coded literals computed
from featuredBg inside toHtml -- promoted to real optional props (each
falling back to the exact prior literal when unset) and exposed via
ColorPickerField in PricingStylePanel.

SocialStylePanel now exposes SocialLinks' iconShape/gap (already-built
props with no control), plus Icon's bgColor/bgShape/bgSize/link and
StarRating's filledColor/emptyColor, which the panel's generic
iconBgColor/starColor checks never matched since those aren't Icon's or
StarRating's real prop names.

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

craft/src/components/sections/Countdown.tsx

@@ -11,6 +11,11 @@ interface CountdownProps {
   labelColor?: string;
   bgColor?: string;
   anchorId?: string;
+  animation?: string;
+  animationDelay?: string;
+  hideOnDesktop?: boolean;
+  hideOnTablet?: boolean;
+  hideOnMobile?: boolean;
 }
 
 interface TimeLeft {
@@ -139,6 +144,11 @@ Countdown.craft = {
     labelColor: 'rgba(255,255,255,0.7)',
     bgColor: '#18181b',
     anchorId: '',
+    animation: '',
+    animationDelay: '',
+    hideOnDesktop: false,
+    hideOnTablet: false,
+    hideOnMobile: false,
   },
   rules: {
     canDrag: () => true,