The memo-boundary re-render fix needs visual regression evidence that
scroll-back through history tracks correctly rather than freezing on the
newest rows. The screenshot spec captures the post-fix tracking and
top-of-history states under the same mock-relay window semantics the
timeline uses in production.
Also re-points emitMockHistory's since-filter comment at the timeline's
actual live subscription (subscribeToChannel -> buildChannelFilter,
limit:50, no since/until). The prior comment misattributed it to the
huddle-TTS sub, leaving a reader to believe the timeline path exercises
the since branch when it does not.
Co-authored-by: Will Pfleger <pfleger.will@gmail.com>
Signed-off-by: Will Pfleger <pfleger.will@gmail.com>
3bb88894b9