fix(ocr): fix SSE retry to actually reconnect EventSource

The retry button set status='running' but didn't re-trigger the $effect
because jobId hadn't changed. Added retryCount state so the effect
re-runs and creates a fresh EventSource on retry. Also added aria-label
to the progress bar for accessibility.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/lib/components/OcrProgress.svelte

@@ -13,10 +13,12 @@ let processed: number = $state(0);
 let total: number = $state(0);
 let currentPage: number = $state(0);
 let totalPages: number = $state(0);
+let retryCount: number = $state(0);
 
 let progressPercent = $derived(total > 0 ? Math.round((processed / total) * 100) : 0);
 
 $effect(() => {
+	void retryCount; // track dependency to re-create EventSource on retry
 	const source = new EventSource(`/api/ocr/jobs/${jobId}/progress`);
 
 	source.addEventListener('document', (e) => {
@@ -63,6 +65,7 @@ $effect(() => {
 				class="h-full bg-brand-mint transition-all duration-300"
 				style="width: {progressPercent}%"
 				role="progressbar"
+				aria-label={m.ocr_progress_heading()}
 				aria-valuenow={progressPercent}
 				aria-valuemin={0}
 				aria-valuemax={100}
@@ -79,7 +82,7 @@ $effect(() => {
 		</h3>
 		<button
 			type="button"
-			onclick={() => { status = 'running'; }}
+			onclick={() => { retryCount++; status = 'running'; }}
 			class="text-sm font-medium text-brand-navy transition-colors hover:text-brand-navy/80"
 		>
 			{m.ocr_error_retry()}