Record file root sync conflicts

AGENTS.md

@@ -148,7 +148,10 @@ Roadmap items should be actionable and checkable:
   roots from sync-status `cas-tree:<name>` watermarks. `geth cas root apply`
   materializes missing files/directories from a CAS tree without deleting extras
   or overwriting local edits, and records conflicts for manual resolution.
-  Richer three-way file application remains roadmap work.
+  Repeated file-root syncs retain the previous imported remote tree as the
+  base and record durable concurrent edit, delete/edit, and divergent rename
+  conflicts when local and remote roots both changed. Richer three-way file
+  application remains roadmap work.
 - DB resources can be registered locally and report local-only status plus a
   read-only SQLite schema summary/hash and `crsql_changes` metadata when
   present. The DB crate and daemon can extract typed read-only `crsql_changes`