Add a deterministic transition matrix case for a stale prepared metadata snapshot followed by a committed transition, duplicate transition, and late GET. The test proves the stale metadata generation is physically reclaimed, duplicate transition does not upload a second remote candidate, and the late GET reads the committed remote body byte-for-byte instead of reopening the released local source.
Refs rustfs/backlog#1355
Co-authored-by: heihutu <heihutu@gmail.com>