feat: improve admin build (#14485)

#### PR Dependency Tree


* **PR #14485** 👈

This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Chores**
  * Admin static assets now served under /admin for self-hosted installs
  * CLI is directly executable from the command line
  * Build tooling supports a configurable self-hosted public path
  * Updated admin package script for adding UI components
* Added a PostCSS dependency and plugin to the build toolchain for admin
builds

* **Style**
* Switched queue module to a local queuedash stylesheet, added queuedash
Tailwind layer, and scoped queuedash styles for the admin UI

* **Bug Fixes**
  * Improved error propagation in the Electron renderer
* Migration compatibility to repair a legacy checksum during native
storage upgrades

* **Tests**
  * Added tests covering the migration repair flow
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

tools/cli/src/rspack/index.ts

@@ -12,6 +12,7 @@ import { VanillaExtractPlugin } from '@vanilla-extract/webpack-plugin';
 import cssnano from 'cssnano';
 import { compact, merge } from 'lodash-es';
 
+import { queuedashScopePostcssPlugin } from '../postcss/queuedash-scope.js';
 import { productionCacheGroups } from '../webpack/cache-group.js';
 import {
   type CreateHTMLPluginConfig,
@@ -228,6 +229,9 @@ export function createHTMLTargetConfig(
                               require(pkg.join('tailwind.config.js').value),
                             ],
                             ['autoprefixer'],
+                            ...(buildConfig.isAdmin
+                              ? [queuedashScopePostcssPlugin()]
+                              : []),
                           ]
                         : [
                             cssnano({