Add a MoveFile filesystem tool
Merged
YO
18d ago+102+102+012345678901234567890123456789-3-3-0123456789
Filesystem tools (CopyFile, DeleteFile, WriteFile, etc.) don't have a MoveFile counterpart, so an agent can't rename/relocate a file. It can only copy it and then delete the source, which takes two tool calls.
Added the tool modeled on CopyFile, which already had all the needed structure.
Registered it in FileStorage::all() next to the other write tools. Added success and failure tests plus an end-to-end test, updated the tool-count assertions.