round 1: implement bracket-first manual compaction

.agents/notes/implemented/architecture/2026-07-30-session-end-seed-log-boundary.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write .agents/notes/implemented/architecture/2026-07-30-session-end-seed-log-boundary.md
-2026-07-30-session-end-seed-log-boundary.md: 837531ba0bd3ecf404eb47ee933438546c682a54
-2026-07-30-session-end-seed-log-boundary.zh.md: 33680c1845364de62e5b53ead13de418a389f908
+2026-07-30-session-end-seed-log-boundary.md: ce5231d0082360fb6219321365a9fbdc4e4e0d4f
+2026-07-30-session-end-seed-log-boundary.zh.md: 33dacdaaeac665dc6959d40a8cc3ba0bb559e6a2

.agents/notes/implemented/architecture/2026-07-30-session-end-seed-log-boundary.md

@@ -52,4 +52,4 @@ Cost: a seeded session's log is one event longer, which moved seq expectations i
 
 `session/end-seed` joins the on-disk vocabulary. Under the pre-release stance (`SESSION_FORMAT_VERSION` pinned at `0`, no compatibility promise) older logs simply lack it, and a log without a boundary correctly classifies nothing as constructor-seed history.
 
-Not built here: no plugin reads the boundary yet. Wiring the compaction seam's staleness check to it is the follow-up that motivated this boundary; the predicate helper belongs with that seam, where a real consumer decides its shape, rather than shipping into core untested against one.
+The [queued manual compaction decision](../feature/2026-07-30-queued-manual-compaction.md) now supplies the first consumer. Its tail scan independently finds the unmatched `compact/start` and newest end-seed, treats only a start after that boundary as live, and clears the invariant trace on the same replay transition. The predicate remains in the compaction package rather than becoming a generic core helper.

.agents/notes/implemented/architecture/2026-07-30-session-end-seed-log-boundary.zh.md

@@ -52,4 +52,4 @@ Status: implemented
 
 `session/end-seed` 加入了落盘词汇表。在预发布立场下（`SESSION_FORMAT_VERSION` 固定为 `0`，不作兼容承诺），更旧的日志只是没有它，而没有边界的日志会正确地判定没有任何内容属于构造种子历史。
 
-此处未做：还没有任何插件读取该边界。把压缩 seam 的陈旧性检查接到它上面，是催生这条边界的后续工作；谓词辅助函数应当归属那个 seam——在那里由真实消费方决定它的形状——而不是未经真实消费方检验就先落进核心。
+[排队手动压缩决策](../feature/2026-07-30-queued-manual-compaction.md)如今提供了第一个消费方。其尾部扫描会分别查找未匹配的 `compact/start` 与最新 end-seed，只把位于该边界之后的 start 视为活动锁，并在同一个回放转换上清除不变量追踪状态。该谓词仍位于压缩包中，不会成为通用核心辅助函数。