Pin moq-lite-03's "from latest" subscribe semantics: a listener that
joins after the speaker has been broadcasting for a while sees only
new frames, not the pre-subscribe history.
Phase 1: speaker pushes 5 early frames (bytes 0..4) with no listener
attached. The relay does not buffer these in moq-lite-03.
Phase 2: late listener subscribes.
Phase 3: speaker pushes 5 more frames (bytes 100..104). The listener
takes the first 5 frames it sees and we assert ALL of them carry
bytes >= 100 — any contamination from phase 1 fails loudly with
the offending bytes named.
This pins the no-replay guarantee against a future regression to
"buffer-and-replay" behaviour, which would change recovery latency
characteristics for users joining mid-stream.
Claude
dcbe31d4c8