Record file root sync conflicts

README.md

@@ -118,7 +118,9 @@ The bootstrap implementation provides:
 - 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
+  overwriting local edits. Repeated syncs keep the previous imported remote
+  tree as the base and record durable conflicts when local and remote roots
+  both changed.
 - local file conflict metadata commands:
   `geth cas conflict record/list/resolve`
 - local DB resource registration: `geth db add <name> <path>` and
@@ -194,6 +196,10 @@ 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.
+When a previous imported remote tree is available, sync compares that base
+against the current local same-named root and the newly imported remote tree.
+Concurrent edit, delete/edit, and divergent rename conflicts are recorded in
+the local conflict table for later resolution.
 `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.