resolves the currently-open editor project's note id (null ⇒ none).
getDirectoryHandle(create) — create a directory.
getFile().text()/arrayBuffer() — read a file (base64 when binary).
removeEntry — delete a file or directory.
createWritable().write — write a file (data is base64 when binary).
The host-side handler for FS-adapter RPC. A later /api-backed adapter (mapping ops onto linXiv's /api/notes CRUD, or a real on-disk vault) will implement this; the signatures mirror the HostFsAdapter / FsDirHandle method surface the editor consumes. Each method returns the matching FsResult variant (or throws — the client serializes the error into a
texbrain:fs:result { ok: false }).