[cellrishi-code]

Summary

• Add a fixed-capacity, allocation-free RAM filesystem with create, read, write, remove, and path enumeration operations.
• Reject malformed/traversal paths and return explicit errors for missing files, duplicate paths, capacity exhaustion, and oversized writes.
• Exercise the filesystem during kernel boot with a /welcome.txt smoke check.
• Document current limitations and the roadmap toward a VFS and persistent storage.

Validation

• Added unit tests for CRUD operations, path validation, duplicate paths, capacity exhaustion, and oversized writes.
• The GitHub connector cannot run the Rust toolchain or QEMU here, so cargo fmt, cargo check, cargo test, Clippy, and boot verification still need to be run in CI/local environment.

Scope note

This is the first RAM-backed milestone, not a persistent on-disk filesystem. Contents are volatile and disappear on reboot.