ui: extract shared ActivityTable and split ModelDetail into components

- Add ActivityTable component consolidating column customization,
  table rendering, pagination, and capture dialog previously
  duplicated between Activity.svelte and ModelDetail.svelte
- Split ModelDetail tabs into ModelActivityTab, ModelLogsTab, and
  ModelDetailsTab components under components/model/
- Reduce Activity.svelte and ModelDetail.svelte to thin shells

- ModelDetail tabs now reuse ActivityTable instead of duplicating
  column management, formatting, and capture logic

ui-svelte/src/components/model/ModelActivityTab.svelte

@@ -0,0 +1,24 @@
+<script lang="ts">
+  import { metrics } from "../../stores/api";
+  import ActivityTable from "../ActivityTable.svelte";
+
+  interface Props {
+    modelId: string;
+  }
+
+  let { modelId }: Props = $props();
+
+  let modelMetrics = $derived(
+    [...$metrics].filter((m) => m.model === modelId).sort((a, b) => b.id - a.id)
+  );
+</script>
+
+<ActivityTable
+  metrics={modelMetrics}
+  storagePrefix="model-detail"
+  showModelColumn={false}
+  showPagination={true}
+  compact={true}
+  title="Recent Activity"
+  emptyMessage="No activity recorded for this model"
+/>