test(podcasts): the briefing acceptance plays the born-reversed order

The §0-item-2 acceptance pin predates the chain-order system and
assumed the native default: it started the chain at feed position 1
and expected a forward hop. With the born-reversed default (d56031f3),
the page's first card is feed position 5 and the chain runs 5 → 1 —
the acceptance's MEANING is unchanged (play from the first card you
see, chained back-to-back within the live briefing set); the fixture
card it starts from flipped accordingly. Changelogged.

This was the only failure in the full-suite validation run (154s,
green) — the first whole-suite pass across today's four units
(chips, label endpoint, apply-path seed, born-reversed acceptance).

docs/contract_pins.md

@@ -714,3 +714,9 @@ Explicit values (client-sent or stored — e.g. a deliberate native)
 are never clobbered. Pinned (TestSmartCollectionBornReversed):
 apply-seeds-when-unordered, respects stored native, respects client
 native.
+
+TestPodcastSmartCollections' acceptance pin updated with the same flip:
+the briefing acceptance now starts from the page's FIRST card (feed
+position 5 — the born-reversed default's book order) and chains into
+feed position 1. The acceptance meaning is unchanged: play from what
+you see, chained back-to-back within the live briefing set.