meta: ignore AI assistants files

[mcollina]

• Add CLAUDE.md and AGENTS.md to .gitignore under a new AI assistants section
• Exclude them from markdown linting in Makefile via $(filter-out ...)
• Exclude them from ESLint markdown processing in eslint.config.mjs

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.75%. Comparing base (4f08c64) to head (d6611f6).

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #62612      +/-   ##
==========================================
- Coverage   89.75%   89.75%   -0.01%     
==========================================
  Files         696      696              
  Lines      214812   214812              
  Branches    41108    41107       -1     
==========================================
- Hits       192801   192798       -3     
+ Misses      14120    14108      -12     
- Partials     7891     7906      +15     

see 28 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.