Add safe file-root apply

README.md

@@ -108,9 +108,10 @@ The bootstrap implementation provides:
   `unpin`, `cleanup`, `providers`, `list`; remote fetch accepts
   `--bearer-secret <secret>`
 - local CAS tree objects describe file trees and are stored as CAS blobs
-- local file-root commands: `geth cas root add/list/scan/sync`; root sync pulls
-  authorized remote tree metadata and CAS tree bytes into a peer-qualified
-  remote root without writing files
+- local file-root commands: `geth cas root add/list/scan/sync/apply`; root sync
+  pulls authorized remote tree metadata and CAS tree bytes into a peer-qualified
+  remote root, and apply materializes a tree without deleting files or
+  overwriting local edits
 - local file conflict metadata commands:
   `geth cas conflict record/list/resolve`
 - local DB resource registration: `geth db add <name> <path>` and
@@ -180,6 +181,9 @@ local daemon skip unchanged or unauthorized streams.
 File roots advertise `cas-tree:<name>` watermarks when the caller has
 `cas.fetch`; background live-sync imports updated tree metadata and CAS tree
 bytes into peer-qualified remote roots without writing files.
+`geth cas root apply <root> --to <path>` can then materialize that tree locally:
+it creates missing directories/files, never deletes extra files, never
+overwrites differing local files, and records conflicts for manual resolution.
 Named KV stores participate in the same live-sync loop once they exist locally:
 manual `geth kv sync <node-id> <name>` and background ticks require `kv.read`
 on the remote `resource:kv:<name>` and import only remote entries that are not