feat(admin): surface skipped file count in ImportStatusCard

Adds SkippedFile to the local ImportStatus type and updates
ImportStatusCard to show an amber skipped-count section with a
collapsible filename list in the DONE state. Only rendered when
skipped > 0. i18n keys added for de/en/es.

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

frontend/src/routes/admin/system/ImportStatusCard.svelte

@@ -48,6 +48,21 @@ const failureMessage = $derived(
 			</p>
 			<p class="mt-1 text-xs text-green-800">{m.admin_system_import_status_done()}</p>
 		</div>
+		{#if importStatus.skipped > 0}
+			<details class="mb-4 rounded-sm border border-amber-200 bg-amber-50 p-4 text-amber-700">
+				<summary class="cursor-pointer list-none">
+					<p data-testid="skipped-count" class="text-base font-bold">{importStatus.skipped}</p>
+					<p class="font-sans text-xs font-bold tracking-widest text-amber-800 uppercase">
+						{m.admin_system_import_skipped_label()}
+					</p>
+				</summary>
+				<ul class="mt-3 space-y-1">
+					{#each importStatus.skippedFiles as { filename, reason } (filename)}
+						<li class="font-mono text-xs text-ink-2">{filename} — {reason}</li>
+					{/each}
+				</ul>
+			</details>
+		{/if}
 		<button
 			data-import-trigger
 			onclick={ontrigger}