- Refactor should_forward_pli(room, stream_id) -> should_forward_pli(room, stream_id, now: Instant)
so the 200 ms dedup window is deterministically testable.
- Update the one caller in run_participant_signals to pass Instant::now().
- Add 6 PLI unit tests covering:
* first PLI forwards
* duplicate within 200 ms suppressed
* after 200 ms forwards again
* different streams independent
* different rooms independent
* no stream owner returns None
Addresses reviewer CR on T4.7 (line drawn at T4.6 — stateful relay features must
have state-transition tests).
wzp-relay tests: 93 -> 99 pass.
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