create a new particle with modified content and link it to the previous version
editing does not mutate — it creates. the old particle keeps its Hemera hash. the new particle gets a new hash. a cyberlink from old → new records the succession
particle_v1 (hash_1) ──"next"──→ particle_v2 (hash_2)
the version chain is traversable in both directions (via backlinks). every version is permanent, addressable, and carries its own cyberank
see cyb/fs for the filesystem model. see cyb/fs/patch for batch operations over multiple particles