fix: ConfirmDialog accessibility and standardize destructive action confirmations

- Add focus trap, Escape key handling, ARIA attributes to ConfirmDialog
- Replace native confirm() with ConfirmDialog for stage, registry, user deletion
- Add confirmation dialogs for env variable and volume deletion

web/src/routes/settings/registries/+page.svelte

@@ -7,6 +7,7 @@
 	import { toasts } from '$lib/stores/toast';
 	import { t } from '$lib/i18n';
 	import { IconPlus, IconLoader, IconEdit, IconTrash, IconWifi } from '$lib/components/icons';
+	import ConfirmDialog from '$lib/components/ConfirmDialog.svelte';
 
 	let registries = $state<Registry[]>([]);
 	let loading = $state(true);
@@ -22,6 +23,7 @@
 	let testingId = $state<string | null>(null);
 	let healthStatus = $state<Record<string, 'checking' | 'healthy' | 'unhealthy'>>({});
 
+	let registryDeleteTarget = $state<Registry | null>(null);
 	let errors = $state<Record<string, string>>({});
 
 	function validateForm(): boolean {
@@ -59,7 +61,6 @@
 	}
 
 	async function handleDelete(registry: Registry) {
-		if (!confirm($t('settingsRegistries.deleteConfirm', { name: registry.name }))) return;
 		try { await deleteRegistry(registry.id); toasts.success($t('settingsRegistries.registryDeleted', { name: registry.name })); await loadRegistryList(); }
 		catch (err) { toasts.error(err instanceof Error ? err.message : $t('settingsRegistries.deleteFailed')); }
 	}
@@ -174,10 +175,24 @@
 							{testingId === registry.id ? $t('settingsRegistries.testing') : $t('settingsRegistries.test')}
 						</button>
 						<button onclick={() => startEdit(registry)} class="rounded-lg p-2 text-[var(--text-tertiary)] hover:bg-[var(--surface-card-hover)] hover:text-[var(--text-link)] transition-colors"><IconEdit size={16} /></button>
-						<button onclick={() => handleDelete(registry)} class="rounded-lg p-2 text-[var(--text-tertiary)] hover:bg-red-50 hover:text-red-600 transition-colors"><IconTrash size={16} /></button>
+						<button onclick={() => { registryDeleteTarget = registry; }} class="rounded-lg p-2 text-[var(--text-tertiary)] hover:bg-red-50 hover:text-red-600 transition-colors"><IconTrash size={16} /></button>
 					</div>
 				</div>
 			{/each}
 		</div>
 	{/if}
 </div>
+
+<ConfirmDialog
+	open={registryDeleteTarget !== null}
+	title={$t('settingsRegistries.deleteTitle')}
+	message={$t('settingsRegistries.deleteConfirm', { name: registryDeleteTarget?.name ?? '' })}
+	confirmLabel={$t('common.delete')}
+	confirmVariant="danger"
+	onconfirm={async () => {
+		const reg = registryDeleteTarget;
+		registryDeleteTarget = null;
+		if (reg) await handleDelete(reg);
+	}}
+	oncancel={() => { registryDeleteTarget = null; }}
+/>