Optimize test runner

[Chemaclass]

📚 Description

Performance optimizations to reduce subprocess overhead in the test runner.

🔖 Changes

• Replace type -t with declare -F for faster function existence checks
• Optimize base64 encoding (use printf | base64 -w 0 instead of echo | base64 | tr)
• Combine grep and sed operations in data provider lookup (single sed -nE pass)
• Use case statement instead of tr subprocess for string capitalization
• Cache state values to avoid repeated subshell invocations
• Initialize temp directory once at startup instead of per temp_file() call

🖼️ Demo

BEFORE

AFTER

✅ To-do list

• I updated the CHANGELOG.md to reflect the new feature or fix
• I updated the documentation to reflect the changes