rendering for "webruntime/appXk3ja79" failed. Reason: 404 when using the plugin

Start with the sf lightning dev site -n sitename entry point and reproduce using lightning-dev 1.2.0 on the reported custom LWR Site. Investigate the lightning/alert 404 and LWR.define is not a function errors; done means the site opens in a browser without these errors.

Summary

Unable to use the plugin with the custom LWR Site.

Steps To Reproduce:

1. Upgrade/install version v1.2.0
2. Try to run command sf lightning dev site -n sitename (replace sitename with your site)
3. Open the browser inspect element

Expected Result

Site to open in a browser tab

Actual Result

Following errors are shown

rendering for "webruntime/appXk3ja79" failed. Reason: 404: Could not find module with specifier "lightning/alert"
Uncaught TypeError: LWR.define is not a function

Additional Information

System Information

SF CLI:

Terminal : zsh
OS: MacOS Sequoia

{
  "architecture": "darwin-arm64",
  "cliVersion": "@salesforce/cli/2.57.7",
  "nodeVersion": "node-v20.16.0",
  "osVersion": "Darwin 24.0.0",
  "rootPath": "/Users/lakshma.kusam/.local/share/sf/client/2.57.7-291554e",
  "shell": "zsh",
  "pluginVersions": [
    "@oclif/plugin-autocomplete 3.2.2 (core)",
    "@oclif/plugin-commands 4.0.13 (core)",
    "@oclif/plugin-help 6.2.10 (core)",
    "@oclif/plugin-not-found 3.2.18 (core)",
    "@oclif/plugin-plugins 5.4.6 (core)",
    "@oclif/plugin-search 1.2.7 (core)",
    "@oclif/plugin-update 4.5.5 (core)",
    "@oclif/plugin-version 2.2.11 (core)",
    "@oclif/plugin-warn-if-update-available 3.1.13 (core)",
    "@oclif/plugin-which 3.2.12 (core)",
    "@salesforce/cli 2.57.7 (core)",
    "apex 3.4.5 (core)",
    "api 1.2.1 (core)",
    "auth 3.6.51 (core)",
    "data 3.6.3 (core)",
    "deploy-retrieve 3.12.0 (core)",
    "info 3.4.2 (core)",
    "lightning-dev 1.2.0 (user) published 5 days ago (Fri Sep 13 2024)",
    "limits 3.3.27 (core)",
    "marketplace 1.2.24 (core)",
    "org 4.5.4 (core)",
    "packaging 2.8.0 (core)",
    "schema 3.3.26 (core)",
    "settings 2.3.15 (core)",
    "sobject 1.4.32 (core)",
    "source 3.5.16 (core)",
    "telemetry 3.6.10 (core)",
    "templates 56.3.14 (core)",
    "trust 3.7.25 (core)",
    "user 3.5.26 (core)",
    "sfdmu 4.36.0 (user) published 11 days ago (Sat Sep 07 2024)"
  ]
}

OS:
MacOS Sequoia