fix: address review round next

- subagents.history computes its projections best-effort on both arms
  (a hostile unit's fold rejection serves the page without the block,
  matching the session-list precedent) with dual-arm coverage
- the lifecycle-witness spec probes every field of the seven-key
  witness, protecting the key list itself
- list-children's own module docs catch up with the seq-gate contract,
  and the design note records the rung-two later-event window as an
  accepted, self-healing deviation of the corruption class

.agents/notes/implemented/architecture/2026-08-06-subagent-list-identity-projection.md

@@ -128,6 +128,7 @@ Known boundary deviations (deliberately accepted, recorded with this note):
 - A live/persisted header conflict: the old implementation made it per-child corrupt; enumeration now prefers live with no consistency check, the conflict goes unnoticed, and the live record forms the row.
 - A source-read failure on damaged storage (e.g. a bad surface rejected by the cold full read): the old implementation mapped it to per-child `corrupt`; it is now uniformly an `unavailable` row (the read side cannot tell the causes apart).
 - An unknown parent: the old implementation threw not-found through session-query ('parent session … was not found'); the subagent-owned merge now yields an empty subset for a nonexistent parent, enumeration returns an empty list, and later operations on the wire land as child-level subagent-not-found — a silent change of semantics and wording, recorded as explicitly accepted.
+- Rung 2's later-event window: a cache row lands right after the first own descriptor, the log then appends a second own descriptor (or a malformed payload setting the null sentinel), and the process crashes before the next checkpoint — from then on a cold listing's rung 2, admitted by the seq≥seedLength gate, keeps serving the row's old identity (the first own descriptor's value), diverging from the authoritative refold (last-wins, the second), and a rung-2 hit triggers no refold, so nothing notices. Three boundaries: ① the precondition is a second own descriptor on the same child, violating the establishing provider's append-exactly-once contract — corruption-class data, same family and source as the multi-descriptor deviation; ② it takes both "corruption + a crash missing every checkpoint (the two mandatory points, turn/end and disposal, and the count/interval throttle points all unmet)" at once; ③ a healthy child (exactly one own descriptor) is unaffected — what the seq gate admits is precisely the only true identity. Self-healing: any live run of that child (the turn/end mandatory checkpoint) or any moment that triggers cache.write overwrites the whole row with a fresh fold (whole-record replace), and rung 2 serves correctly from then on; the authoritative paths (the rung-3 refold, the live snapshot, the resume fold) are correct from the start, and the divergence exists only in listing reads while the child stays cold and the row is never rewritten. The mechanical fixes were not taken: gate reconciliation would need the log-end seq, unavailable to a zero-read cold path; a cache row carrying the revision is an opaque token, incomparable and a cross-domain schema change — filed as accepted under the "the cache is never authoritative" doctrine.
 
 Consuming surfaces: diagnostic handling across wire, tool, and GUI **stays entirely as it was, zero changes** (the `list_agents` description and output schema are untouched; the plugin only narrows its load requirement — `sessionQuery` dropped from inject). The only behavioral changes are in apiproxy: on the route segment, the `hasSubagentDescriptor()` scan is deleted and `hasSubagentOwner` looks only at `header.origin` — pre-#1569 data without `origin` is no longer recognized as a subagent owner; it never entered the catalog anyway, and the pre-release stance accepts this; and `subagents.history` is aligned with `session.history`'s source — a live child served from in-memory events and the registry's watermark snapshot, a cold child from `inspectServable` reading persistence directly with a detached fold, no query service involved, the SESSION_QUERY_* error arms retired with it, and the wire shape unchanged (the `history` JSDoc wording becomes the live in-memory snapshot / cold persisted log dual arm).
 
@@ -172,7 +173,7 @@ Consuming surfaces: diagnostic handling across wire, tool, and GUI **stays entir
 - The subagent list no longer requires a query backend: both pure-live and persistence-less deployments can list; `SUBAGENT_CONTROL_SESSION_QUERY_UNAVAILABLE` is gone, and loading the `list_agents` plugin no longer requires `sessionQuery`.
 - Identity interpretation exists only in the single unit registered with the registry: the list's three-rung ladder and GUI history's cold read all use the registry's and the cache's existing reads (snapshot, cachedSnapshot, restore), and no bypass fold exists; if some future consuming surface bypasses the registry with a hand-written fold, values will drift across read faces — a discipline this design requires be maintained, not a mechanical guarantee.
 - Per-child isolation is back: a single child's cold-read failure loses only that row and healthy siblings are unaffected; a persistence listing failure still fails the whole enumeration.
-- The diagnostic and enumeration semantics leaves five boundary deviations (a stillborn fork surfacing under its ancestor's identity, multiple descriptors resolving to the last, header conflicts going unnoticed, damaged-source read failures shifting from `corrupt` to `unavailable`, and an unknown parent yielding an empty list instead of not-found); the full semantics is in the known-boundary-deviations list; the first four are display or classification deviations on debris-grade data with resume authorization unaffected, and the unknown-parent one is a silent query-semantics change, explicitly accepted.
+- The diagnostic and enumeration semantics leaves six boundary deviations (a stillborn fork surfacing under its ancestor's identity, multiple descriptors resolving to the last, header conflicts going unnoticed, damaged-source read failures shifting from `corrupt` to `unavailable`, an unknown parent yielding an empty list instead of not-found, and rung 2's later-event window); the full semantics is in the known-boundary-deviations list; the first four are display or classification deviations on debris-grade data, the unknown-parent one is a silent query-semantics change, and the rung-2 window is a self-healing cache-serving divergence under the double condition of corruption plus a crash; resume authorization is unaffected throughout, all explicitly accepted.
 - Pre-#1569 data without `origin` is no longer recognized as a subagent owner; it never entered the catalog anyway, and pre-release carries no compatibility promise.
 
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