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/frontend/apps/electron/src/helper/index.ts

@@ -25,6 +25,9 @@ function setupRendererConnection(rendererPort: Electron.MessagePortMain) {
             return result;
           } catch (error) {
             logger.error('[async-api]', `${namespace}.${name}`, error);
+            // Propagate errors to the renderer so callers don't receive `undefined`
+            // and fail with confusing TypeErrors.
+            throw error instanceof Error ? error : new Error(String(error));
           }
         };
         return [`${namespace}:${name}`, handlerWithLog];