✨ feat: Add skeleton loading animation to SelectableButtonGroup component (#1365)

Add comprehensive loading state support with skeleton animations for the SelectableButtonGroup component, improving user experience during data loading.

Key Changes:
- Add loading prop to SelectableButtonGroup with minimum 500ms display duration
- Implement skeleton buttons with proper Semi-UI Skeleton wrapper and active animation
- Use fixed skeleton count (6 items) to prevent visual jumping during load transitions
- Pass loading state through all pricing filter components hierarchy:
  - PricingSidebar and PricingFilterModal as container components
  - PricingDisplaySettings, PricingCategories, PricingGroups, PricingQuotaTypes as filter components

Technical Details:
- Reference CardTable.js implementation for consistent skeleton UI patterns
- Add useEffect hook for 500ms minimum loading duration control
- Support both checkbox and regular button skeleton modes
- Maintain responsive layout compatibility (mobile/desktop)
- Add proper JSDoc parameter documentation for loading prop

Fixes:
- Prevent skeleton count sudden changes that caused visual discontinuity
- Ensure proper skeleton animation with Semi-UI active parameter
- Maintain consistent loading experience across all filter components

web/src/components/table/model-pricing/PricingSidebar.jsx

@@ -38,6 +38,7 @@ const PricingSidebar = ({
   setFilterGroup,
   filterQuotaType,
   setFilterQuotaType,
+  loading,
   t,
   ...categoryProps
 }) => {
@@ -77,14 +78,15 @@ const PricingSidebar = ({
         setCurrency={setCurrency}
         showRatio={showRatio}
         setShowRatio={setShowRatio}
+        loading={loading}
         t={t}
       />
 
-      <PricingCategories {...categoryProps} setActiveKey={setActiveKey} t={t} />
+      <PricingCategories {...categoryProps} setActiveKey={setActiveKey} loading={loading} t={t} />
 
-      <PricingGroups filterGroup={filterGroup} setFilterGroup={setFilterGroup} usableGroup={categoryProps.usableGroup} models={categoryProps.models} t={t} />
+      <PricingGroups filterGroup={filterGroup} setFilterGroup={setFilterGroup} usableGroup={categoryProps.usableGroup} models={categoryProps.models} loading={loading} t={t} />
 
-      <PricingQuotaTypes filterQuotaType={filterQuotaType} setFilterQuotaType={setFilterQuotaType} models={categoryProps.models} t={t} />
+      <PricingQuotaTypes filterQuotaType={filterQuotaType} setFilterQuotaType={setFilterQuotaType} models={categoryProps.models} loading={loading} t={t} />
     </div>
   );
 };