feat(chain): implement new chain subsystem with eager evaluation and fluent API

- Introduced `chain` module for lodash-style eager chained array operations.
- Added fluent methods: `map`, `filter`, `sortBy`, `unique`, `chunk`, `take`, `drop`, `flatten`, `reverse`, `slice`, `concat`, `sampleSize`.
- Implemented terminal methods: `value`, `find`, `reduce`, `some`, `every`, `includes`, `sample`.
- Ensured full backward compatibility with existing versions (6.0.0/6.1.0).
- Maintained IE11 compatibility and added subpath export for `chain`.
- Updated documentation and changelog for version 6.2.0.

Author: saqqdy