chore: standardize repository ignore rules

[ryanbarlow97]

Summary

Standardize .gitignore section order and generated-file rules across TF-Minecraft repositories, retaining project-specific exclusions and dependency exceptions. Add /.scratch/ for local investigation notes and test artifacts.

Remove committed Python bytecode; the Python source remains tracked and caches regenerate locally.

Validation: the cross-repository audit passed 9,655 tracked-file and ignore probes across all 39 repositories. No surviving tracked file changed ignore status. Checked scratch/cache ignores, source visibility, dependency and asset exceptions, UTF-8/LF formatting, and git diff --check. Runtime source and build definitions are unchanged.

Documentation impact

No manifest-owned code or configuration paths changed; no system guide or impact waiver is required.

Contract

• Affected behavior: Git hygiene only.
• Tests: 8 documentation manifest tests and the 28-file link check passed. Maven runtime tests are left to CI because source/build definitions are unchanged.
• Player wiki: no change.