feat: add delete button to exports list and detail pages

Add DELETE /api/exports/{id} endpoint with cascade delete, trash icon
buttons on both the exports list and export detail pages, and disable
browser caching for static files to prevent stale JS issues.

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

FabWorks.Api/wwwroot/js/helpers.js

@@ -32,5 +32,19 @@ const api = {
         const r = await fetch(url);
         if (!r.ok) throw new Error(`${r.status} ${r.statusText}`);
         return r.json();
+    },
+    async del(url) {
+        const r = await fetch(url, { method: 'DELETE' });
+        if (!r.ok) throw new Error(`${r.status} ${r.statusText}`);
     }
 };
+
+async function deleteExport(id) {
+    if (!confirm('Delete this export record? This cannot be undone.')) return;
+    try {
+        await api.del(`/api/exports/${id}`);
+        router.dispatch();
+    } catch (err) {
+        alert('Failed to delete: ' + err.message);
+    }
+}