System.FS

Purpose

Filesystem operations with explicit error-returning APIs.

Candidate surface

• FS.ReadAllText(string path) -> Result<string, FsError>
• FS.WriteAllText(string path, string text) -> Result<unit, FsError>
• FS.Exists(string path) -> bool

Notes

• Runtime owns platform-specific I/O behavior.
• Keep path normalization policy explicit and testable.