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 -->

packages/backend/server/package.json

@@ -71,7 +71,7 @@
     "@opentelemetry/semantic-conventions": "^1.38.0",
     "@prisma/client": "^6.6.0",
     "@prisma/instrumentation": "^6.7.0",
-    "@queuedash/api": "^3.14.0",
+    "@queuedash/api": "^3.16.0",
     "@react-email/components": "0.0.38",
     "@socket.io/redis-adapter": "^8.3.0",
     "ai": "^5.0.118",