Automate Markdown List Formatting and LLM Skill Generation

[dgaida]

This PR implements automated improvements to the documentation workflow and adds a new 'Skill' file for LLMs.

Key changes:

1. Markdown List Fixer: Created a utility script pyadm1/utils/fix_markdown_lists.py that ensures all Markdown list items end with two trailing spaces. This is required for correct rendering in some Markdown parsers and was specifically requested by the user.
2. LLM Skill Generation: Created pyadm1/utils/generate_skill_md.py which extracts full docstrings for key classes and methods used in building simulation models. This generates a Skill.md file designed to be consumed by LLMs.
3. CI/CD Integration: Updated .github/workflows/docs.yml to automatically run the list fixer and the skill generator during every documentation build.
4. UI Updates: Added callouts to both English and German versions of the llm_api.md page providing a download link for the generated Skill.md file.

These changes ensure that the documentation remains compliant with the project's formatting standards and provides better support for automated model generation using LLMs.

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PR created automatically by Jules for task 5175681484165727838 started by @dgaida

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