fix(ocr): disable manual annotation drawing while OCR is running

Prevents users from drawing annotations that would be cleared when
the OCR job finishes. transcribeMode is set to false for the PDF
viewer while ocrRunning is true.

Refs #226

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/routes/documents/[id]/+page.svelte

@@ -354,7 +354,7 @@ onMount(() => {
 				fileUrl={fileUrl}
 				isLoading={isLoading}
 				error={fileError}
-				transcribeMode={transcribeMode}
+				transcribeMode={transcribeMode && !ocrRunning}
 				blockNumbers={blockNumbers}
 				annotationReloadKey={annotationReloadKey}
 				annotationsDimmed={transcribeMode && panelMode === 'read'}