Add support for shared configuration file and CLI flags for automation

[jmizell]

Enhancement request:

• Add support for a shared configuration file to be used for a single book processing task, allowing users to specify settings in a reusable config file.
• Add CLI flags to the scripts so they can be integrated with automation tools, scripts, or large language models (LLMs).
• The goal is to allow the same set of GUI tools to be scripted, making it possible for LLMs or scripts to drive the process end-to-end.

This will make the processing pipeline more flexible, automatable, and easier to use in both manual and automated environments.

Requested by: @jmizell