fix: enable page virtualization in worksheet creator

Only pass initialPreview to WorksheetPreview when viewing a shared
worksheet (isFromShare). In the worksheet creator, we want
virtualization enabled for performance with multi-page worksheets.

This ensures:
- Worksheet creator: virtualizes pages (lazy render)
- Shared worksheets: shows all pages immediately (no lazy loading)

The page indicator now works correctly in both modes.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

apps/web/src/app/create/worksheets/components/AdditionWorksheetClient.tsx

@@ -137,7 +137,7 @@ export function AdditionWorksheetClient({
             <Panel defaultSize={75} minSize={60}>
               <PreviewCenter
                 formState={debouncedFormState}
-                initialPreview={initialPreview}
+                initialPreview={isFromShare ? initialPreview : undefined}
                 onGenerate={handleGenerate}
                 status={status}
               />

apps/web/src/app/create/worksheets/components/WorksheetPreview.tsx

@@ -115,7 +115,11 @@ function PreviewContent({ formState, initialData, isScrolling = false }: Workshe
   // When initialData is provided (e.g., shared worksheets), show all pages immediately
   // Otherwise use virtualization for performance
   // Store this as state so it persists after initialData is consumed
-  const [shouldVirtualize] = useState(() => !initialData)
+  const [shouldVirtualize] = useState(() => {
+    const shouldVirt = !initialData
+    console.log('[PAGE INDICATOR] Determining shouldVirtualize - initialData:', initialData ? 'provided' : 'none', '-> shouldVirtualize:', shouldVirt)
+    return shouldVirt
+  })
 
   // Initialize visible pages based on whether we should virtualize
   const [visiblePages, setVisiblePages] = useState<Set<number>>(() => {