* fix: reject oversized checkout diffs * fix(diff): keep large previews from disconnecting clients The physical socket limit is an OOM backstop, not a frame-size contract. Bound structured diff construction incrementally and report oversized previews without closing the client's socket. * fix(app): preserve oversized diff state * fix(diff): stay within relay frame limit --------- Co-authored-by: Mohamed Boudra <boudra.moha@gmail.com>