feat(training-history): hide person/type columns for segmentation context

Add showPersonColumns prop (default true) to TrainingHistory.
SegmentationTrainingCard passes false — segmentation is not person-specific.

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

frontend/src/lib/components/SegmentationTrainingCard.svelte

@@ -82,5 +82,8 @@ async function startTraining() {
 	<h3 class="mt-6 mb-3 text-xs font-bold tracking-widest text-ink-3 uppercase">
 		{m.training_history_heading()}
 	</h3>
-	<TrainingHistory runs={(trainingInfo?.runs ?? []).filter((r) => r.modelName === 'blla')} />
+	<TrainingHistory
+		runs={(trainingInfo?.runs ?? []).filter((r) => r.modelName === 'blla')}
+		showPersonColumns={false}
+	/>
 </div>