Incorporate eBraille-Checker

Now DAISY Pipeline has DTBook to eBraille and EPUB 3 to eBraille scripts, which can be used from Pipeline's GUI. At the same time eBraille Checker is a commandline tool, and many people are not able to use it.
In fact eBraille Checker was released in 2025, but we do not see wide usage due to two reasons.
* Many eBraille producers are not fluent commandline users.
* Many people do not know about eBraille Checker.
By making eBraille Checker work through Pipeline user interface, we will solve multiple problems at once.
The link to eBraille Checker has been placed on daisy.org eBraille webpage, which may help in discovery, but still the challenge of using command line tool will limit its usage.

[https://github.com/daisy/ebraille-checker](https://github.com/daisy/ebraille-checker)

Start by reviewing the linked eBraille Checker repository and the existing DTBook-to-eBraille and EPUB 3-to-eBraille scripts exposed through the Pipeline GUI. Determine the integration entry point and dependencies, with done meaning users can run eBraille Checker through the Pipeline interface without using the command line.

Written by the indexing model from the issue text.