hygiene: README hardening (CQRS + content-hash) + shard 0320Z

docs/hygiene-history/ticks/2026/04/29/0320Z.md

@@ -0,0 +1 @@
+| 2026-04-29T03:20:00Z (autonomous-loop tick — README hardening with CQRS lineage + content-hash naming + closed 5 stale legacy DIRTY PRs) | opus-4-7 / session continuation | 26f978a2 | Material-tick. Closed PRs #718-#722 as transport-superseded by Option B (forward-fix only per Amara's recommendation; tick row content preserved in PR commit history + conversation log). Multi-AI converged refinement received (Gemini CQRS/Event Sourcing lineage + Ani museum-rule compression + Claude.ai operator-authority criterion + review/decay schema + Alexa enthusiasm + Amara final synthesis). Added to shard README: CQRS lineage section (shards = write model / event store; aggregate table = read model / projection; generator = projector run async); content-hash filename recommendation (`HHMMSSZ-<short-content-hash>.md`) for multi-agent / high-concurrency. B-0096 update DEFERRED (PR #732 not yet merged; would conflict). Operator-authority criterion (4-condition rule) recorded as candidate substrate; NOT promoted to glossary entry this round per absorb-without-integrating. Cron `26f978a2` armed. | (PR #735 — README hardening + shard) | Observation — closing 5 legacy DIRTY PRs is the first concrete legacy-drain action. 6 fewer PRs in the queue. The pattern that produced them is structurally fixed (Option B); the queue residue from the pathology is now drained. Forward-fix only; legacy chain doesn't get rewritten into shards. |

docs/hygiene-history/ticks/README.md

@@ -12,6 +12,28 @@ external-AI reviewer 2026-04-29): every tick-history PR added a
 row to the same EOF surface, and parallel in-flight PRs
 conflicted with each other, generating recursive maintenance work.
 
+## External lineage — Git-native CQRS / Event Sourcing
+
+The shard transport maps cleanly onto well-established
+software architecture patterns (per the multi-AI convergence
+2026-04-29):
+
+- **Shard files = write model / event store.** Each shard is
+  an immutable per-tick event. High-concurrency writes are
+  collision-free because each event is a unique file.
+- **Aggregate table = read model / projection.** The legacy
+  `docs/hygiene-history/loop-tick-history.md` is a
+  materialized view derived from the event stream.
+- **Generator = projector.** Updates the read model from the
+  event store on a separate cadence — NEVER inside a shard PR
+  (or the EOF-collision returns at the projection layer).
+
+External anchors: Microsoft's CQRS guidance describes
+separating read and write models; Event Sourcing literature
+treats the event store as the source of truth with read models
+generated on demand. The Git-native version replaces the SQL
+event store with timestamped Markdown files in this directory.
+
 Per task #276 architectural choice (per-tick shard files —
 "Option B"), each tick now writes a unique shard file at:
 
@@ -53,6 +75,25 @@ If a tick lands within the same minute as a prior tick (rare —
 the autonomous-loop cron is `* * * * *`), append `-01`, `-02`,
 ... to disambiguate: `0215Z-01.md`, `0215Z-02.md`.
 
+**Recommended naming for multi-agent / high-concurrency**
+(per the 2026-04-29 multi-AI hardening review):
+
+```text
+docs/hygiene-history/ticks/YYYY/MM/DD/HHMMSSZ-<short-content-hash>.md
+```
+
+Why content-hash:
+
+- **Idempotent**: same content + same second = same path; the
+  Git tree naturally deduplicates.
+- **Collision-discriminating**: different content + same second
+  = different path automatically.
+- **No coordination required** between concurrent writers.
+
+Either form (`HHMMZ.md` or `HHMMSSZ-<short-content-hash>.md`)
+is valid; the second is preferred when concurrency pressure is
+expected.
+
 ## What goes in a shard
 
 The same content that previously appended as a row to the legacy