fix(apiproxy): harden cold session metadata probing

docs/subsystems/session.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 docs/subsystems/session.md
-session.md: 4c40971fe58952b32635aa5eb767a42f73108b00
-session.zh.md: d958b03fcdad91b58cc277636e599cce46a2c7fb
+session.md: 760a3042724472b5f518896b8ff0e56bcfec2799
+session.zh.md: 8c56029af5144569f1ab6df73a8fe2278f9ef5b4

docs/subsystems/session.md

@@ -586,7 +586,7 @@ An explicitly supplied empty seed writes `session/end-seed` at seq 0, which dist
 
 It exists because seed history and live work are otherwise byte-identical, which defeats any plugin owning a standalone open/close bracket: an unmatched `compaction/start` reads the same whether the writer crashed mid-compaction or is compacting right now. An opening marker before `session/end-seed` came from the constructor seed and belongs to an ended lifecycle, whatever ended it (a crash, a succeeding process, or a fork out of a still-running parent), so its owner may treat it as dead. That covers only brackets *this* session inherited: a concurrently live session holding an open bracket over the same history has its own boundary elsewhere, so tolerating concurrent writers needs a liveness signal beyond the log. Core writes the boundary and reads nothing from it — a bracket's vocabulary stays with its owning plugin, which is why crash repair closes turn/step/tool boundaries and never `compaction/*`.
 
-Activity ordering excludes the boundary through `lastActivityTime(events)`: picking a session up is not work, and lazy resume means browsing writes one, so a resume picker or session list ordering by log tail would float every opened session to the top.
+Consumers that order Sessions by human activity exclude this boundary: picking a Session up is not work, so ordering by the log tail would float every opened Session to the top.
 
 ## Plugin-contributed log-only events
 

docs/subsystems/session.zh.md

@@ -590,7 +590,7 @@ interface TurnEndReasonMap {
 
 它之所以必要，是因为种子历史与实时工作在字节层面完全相同，这会让任何拥有独立开／闭括号的插件失效：一个未配对的 `compaction/start`，无论写入方是在压缩中途崩溃、还是此刻正在压缩，读起来都一样。在 `session/end-seed` 之前的开启标记来自构造种子，并且属于一个已结束的生命周期，无论结束原因为何（崩溃、进程接替，或从仍在运行的父会话 fork 出来），因此其所有方可以视之为已死。这只覆盖*本*会话继承的括号：另一个并发存活的会话可能在同一段历史上持有开放括号，而它自己的边界在别处，因此容忍并发写入方还需要日志之外的存活信号。核心写入该边界但不从中读取任何内容——括号的词汇表仍归其所属插件，这也正是崩溃修复只关闭轮次／步骤／工具边界而从不处理 `compaction/*` 的原因。
 
-活动排序通过 `lastActivityTime(events)` 排除该边界：接手会话不算工作，而惰性恢复意味着浏览就会写入一个，因此按日志尾部排序的恢复选择器或会话列表会把每个打开过的会话顶到最前。
+按真人活动排序 Session 的消费方会排除该边界：接手 Session 不算工作，因此按日志尾部排序会把每个打开过的 Session 顶到最前。
 
 ## 插件贡献的仅日志事件