fix: bump comment text to text-base + reload annotations on block delete

Comment text:
- Body and quote bumped from text-sm (14px) to text-base (16px)
  to visually match the font-sans author name at text-sm

Annotation reload on delete:
- Add annotationReloadKey prop through DocumentViewer → PdfViewer
- Increment key after block delete in +page.svelte
- PdfViewer reloads annotations when key changes
- Annotation rectangle disappears immediately, not just after refresh

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

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

@@ -54,6 +54,7 @@ let activeAnnotationId = $state<string | null>(null);
 // ── Transcription blocks ─────────────────────────────────────────────────────
 
 let transcriptionBlocks = $state<TranscriptionBlockData[]>([]);
+let annotationReloadKey = $state(0);
 
 const blockNumbers = $derived(
 	Object.fromEntries(
@@ -92,6 +93,7 @@ async function deleteBlock(blockId: string) {
 	});
 	if (!res.ok) throw new Error('Delete failed');
 	transcriptionBlocks = transcriptionBlocks.filter((b) => b.id !== blockId);
+	annotationReloadKey++;
 }
 
 async function createBlockFromDraw(rect: {
@@ -208,6 +210,7 @@ onMount(() => {
 				error={fileError}
 				transcribeMode={transcribeMode}
 				blockNumbers={blockNumbers}
+				annotationReloadKey={annotationReloadKey}
 				bind:activeAnnotationId={activeAnnotationId}
 				onAnnotationClick={handleAnnotationClick}
 				onTranscriptionDraw={createBlockFromDraw}