Fix Best Practices Docs

Audit all best practices documentation files for issues and fix them. This skill must be run from the brave-core directory.

Step 1: Paths

This skill runs from the brave-core (src/brave) directory. Best practices docs are at ./docs/best-practices/ and the index is at ./docs/best_practices.md.

Set DOCS_DIR="./docs/best-practices".

Step 2: Read All Best Practice Files