enh: update Python version to 3.12 and refine notebook content

[jonas-eschle]

No description provided.

[Copilot]

Pull Request Overview

This PR upgrades the lesson environment to Python 3.12, reorganizes tutorial indices, and enriches the Advanced Classes notebook with decorator and naming-conventions content.

• Updated environment.yml to Python 3.12 and moved zfit packages into main dependencies
• Reordered files in python/README.md and standardized notebook header levels
• Expanded 12AdvancedClasses.ipynb with sections on decorators, naming rules, and refined dunder explanations

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
python/README.md	Reordered operators.md, removed scripting.md from the TOC
python/01basics.ipynb	Changed # Jupyter to ## Jupyter for consistent heading levels
environment.yml	Bumped Python to ~=3.12.0, added zfit & zfit-physics
advanced-python/12AdvancedClasses.ipynb	Added decorators overview, naming conventions, and updated dunder examples

Comments suppressed due to low confidence (1)

python/README.md:55

• You’ve removed scripting.md from the index. Make sure the file itself is deleted (if obsolete) or update any links elsewhere to prevent broken references.

    methods.md

[Copilot]

The hard-coded divisor 100 (and multiplier 4.0) is a magic number. Consider extracting these into named constants or documenting the scaling logic for clarity.

Suggested change

	" return 4.0 * self.avg(scores)/100."
	" return self.GPA_SCALE * self.avg(scores)/self.PERCENTAGE_DIVISOR"