[WIP] Create static documentation site with GitHub Pages

[Copilot]

Thanks for assigning this issue to me. I'm starting to work on it and will keep this PR's description up to date as I form a plan and make progress.

Original prompt

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This section details on the original issue you should resolve

<issue_title>feature: static docs site in GitHub Pages</issue_title>
<issue_description>Create a static documentation site using GitHub pages and Hugo. Create a GitHub action to test the site build on PR and to deploy the site on merge to main. Use path filters on the action to only run when site data has changed. Select an appropriate theme.

Base you documentation on the code in the refactor/cwd branch. This uses a recursive DP approach to determining the directory for a given command.

Use a subdirectory for the docs: docs. Overwrite what is there but include the existing documents in the new site.

Review the code in the repo and cover:

1. Porch basics
   1. Why you would use it
   2. Path inheritance
2. Each command type (one per page)
3. Controlling output
   1. LOG_LEVEL
   2. Stdout and StdError
   3. Colour / no-color
4. The TUI

Path inheritance

The default is to use relative paths. If you specify a command with an absolute path then it will not be changed.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes feature: static docs site in GitHub Pages #33

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