fix(desktop): restore managed Node server startup (#348)

## Summary
- revert the Bun standalone desktop packaging path and restore the
server's original `dist/bin.js` bootstrap flow
- add a managed Node runtime for Electron and Tauri that downloads only
the current platform/arch artifact into `~/.config/codenomad`
- update desktop startup and packaging scripts so packaged apps use the
managed runtime consistently, and clean up Electron's expected
navigation-abort log noise

## Testing
- npm run typecheck --workspace @neuralnomads/codenomad-electron-app
- cargo check
- npm run build --workspace @neuralnomads/codenomad
- npm run build:mac --workspace @neuralnomads/codenomad-electron-app
- launch
`packages/electron-app/release/mac-arm64/CodeNomad.app/Contents/MacOS/CodeNomad`
and verify the packaged server reaches ready with the managed Node
runtime

packages/server/src/index.ts

@@ -29,14 +29,13 @@ import { SideCarManager } from "./sidecars/manager"
 import { ClientConnectionManager } from "./clients/connection-manager"
 import { PluginChannelManager } from "./plugins/channel"
 import { VoiceModeManager } from "./plugins/voice-mode"
-import { readServerPackageVersion, resolveServerPublicDir } from "./runtime-paths"
 
 const require = createRequire(import.meta.url)
 
-const packageJson = { version: readServerPackageVersion(import.meta.url) }
+const packageJson = require("../package.json") as { version: string }
 const __filename = fileURLToPath(import.meta.url)
 const __dirname = path.dirname(__filename)
-const DEFAULT_UI_STATIC_DIR = resolveServerPublicDir(import.meta.url)
+const DEFAULT_UI_STATIC_DIR = path.resolve(__dirname, "../public")
 
 interface CliOptions {
   host: string