v0.13.120: v0.13.120

@newsroom.writer: "What sgit does that Git does not" corrected and extended from the sgit CLI team's review, on the record: the 29-minute figure attributed to cli.sgit.ai, two claims made less strong (TM-R01, TM-R42), what sgit already does added (named-file commits, rotation, mirror, vault-carried policy, rewind refusal, secret guard, cache reads, serve), Git's lead reframed as mostly buildable, and what a host that reads nothing never can.