♻️ refactor(mq-lang): split module_tests.mq into per-module test files

[harehare]

Summary

Split the combined module_tests.mq into module_test.mq files (csv, json, toml, yaml, xml, toon, fuzzy, section, table, semver, md) so each module's tests live independently. Update justfile's test-mq recipe to glob crates/mq-lang/modules/*_test.mq so all module test files run.

Type of Change

• 🐛 Bug fix
• ✨ New feature
• ♻️ Refactor
• 📝 Documentation
• ⚡ Performance
• ✅ Test
• 📦 Build / dependencies
• 👷 CI

Checklist

• I ran cargo fmt and cargo clippy and addressed any warnings
• I ran just test-all and all tests pass
• I added or updated tests covering this change
• I updated relevant documentation (/docs, crate README.md) if needed
• I added a changelog entry if this is a user-facing change

Additional Context

[codspeed-hq]

Merging this PR will not alter performance

✅ 31 untouched benchmarks

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_{Comparing refactor/split-module-tests (af27bb7) with main (bbce7d1)¹}

Footnotes

1. No successful run was found on main (7cd14de) during the generation of this report, so bbce7d1 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩