Improve constraint handling, typing, and doc

[duembgen]

This pull request introduces several improvements and refactorings to the constraint generation and template learning modules, focusing on type safety, code clarity, and efficiency.

Type hints, docstrings, and code standards:

• Added a .github/copilot-instructions.md file specifying code style and documentation guidelines for future development.
• Added type hints, and assertions throughout the code base to improve readability.
• Added module-level docstrings and function docstrings where relevant.

Refactoring constraint and template methods:

• Refactored constraint retrieval in popcor/auto_template.py by merging and improving get_A_list and get_A_b_list into a single method that returns both constraint matrices and right-hand sides.
• Updated template creation accordingly.

Documentation and configuration improvements:

• Updated Sphinx documentation configuration to prevent inherited docstrings from parent classes, ensuring only relevant documentation is shown for subclasses.