feat: enhance frontend UI — command palette, admin redesign, API coverage

Types + API:
- Add User, TemplatePreview, QueueCustomField types
- Add getUsers, getTemplates, createTemplate, updateTemplate,
  previewTemplate, updateQueue, updateLifecycle, updateCustomField API functions

UI:
- Command palette: keyboard-first navigation with fuzzy ticket search
- Admin: comprehensive redesign with tab-based layout (Queues, Lifecycles,
  Scrips, Custom Fields, Templates, Users)
- Ticket list: improved inbox-style rows with quick actions
- Ticket detail: enhanced conversation thread and properties sidebar
- App shell: sidebar visual refinement with active indicator bar
- Theme toggle: smoother transitions

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

web/next.config.ts

@@ -1,11 +1,19 @@
+import { dirname } from "node:path";
+import { fileURLToPath } from "node:url";
 import type { NextConfig } from "next";
 
+const appRoot = dirname(fileURLToPath(import.meta.url));
+
 const nextConfig: NextConfig = {
+  outputFileTracingRoot: appRoot,
+  turbopack: {
+    root: appRoot,
+  },
   async rewrites() {
     return [
       {
-        source: '/api/:path*',
-        destination: 'http://127.0.0.1:9876/:path*',
+        source: "/api/:path*",
+        destination: "http://127.0.0.1:9876/:path*",
       },
     ];
   },