The check_run event is triggered when a check (such as a code quality check) completes, including when the status of a check changes. By adding this event as a trigger, you can initiate a follow-up workflow when the code quality integration finishes its checks.
Reference:
https://docs.github.com/en/actions/reference/workflows-and-actions/events-that-trigger-workflows

[D] GitHub Actions now supports a concurrency key at both the workflow and job level that will ensure that only a single run or job is in progress.
concurrency
Use concurrency to ensure that only a single job or workflow using the same concurrency group will run at a time.
Example: Using concurrency and the default behavior
The default behavior of GitHub Actions is to allow multiple jobs or workflow runs to run concurrently. The concurrency keyword allows you to control the concurrency of workflow runs.
Reference:
https://github.blog/changelog/2021-04-19-github-actions-limit-workflow-run-or-job-concurrency/
https://docs.github.com/en/actions/reference/workflows-and-actions/workflow-syntax#concurrency
https://github.com/marketplace/actions/actions-mutex

The publish-npm job includes the JS-DevTools/npm-publish action, which is used to publish an npm package to an npm registry.
The publish-npm job has the needs: build directive, meaning it will only run after the build job successfully completes.

In a workflow that runs on a pull request comment the event context contains the webhook payload. With github.event you can read the structured fields for the comment text and the pull request number. The comment text is available under the comment body field and the pull request number is available under the issue number for comment events or under the pull request number for pull request events. This makes github.event the direct and convenient source for these values.

Types of actions
Docker container actions. Docker containers package the environment with the GitHub Actions code. ...
JavaScript actions. JavaScript actions can run directly on a runner machine, and separate the action code from the environment used to run the code. ...
Composite Actions.
Note:
JavaScript actions
JavaScript actions can run directly on a runner machine, and separate the action code from the environment used to run the code. Using a JavaScript action simplifies the action code and executes faster than a Docker container action.
Reference:
https://docs.github.com/en/actions/concepts/workflows-and-actions/custom-actions