Phase 3: per-member namespacing — schema 5 (the core group conversion)

One shared vault, per-member namespaces for all churn-prone state:
- _agent/members/<member>/{preferences,current-context,heartbeat,inbox}.md
  + _agent/sessions/<member>/ session logs; shared group-profile.md
  (with auto-rostered ## Members) and inbox/captures/group.md.
- Self-onboarding: load detects a bootstrapped vault lacking THIS
  member's namespace and seeds it (bootstrap.member_bootstrap()).
- load = 8 reads (marker, group profile, my prefs/context/heartbeat,
  shared daily, my inbox, group inbox); heartbeat fallback lists my
  sessions dir; scope show/set is per member.
- Member-tagged shared writes: daily Agent Log lines and entity-update
  dated blocks are '- YYYY-MM-DD [member]: …'; capture --inbox targets
  my inbox; triage lists both inboxes and writes attributed audit lines.
- routing.json: member-anchors / inbox-group / member-segmented session
  routes; single-user anchor paths retired (schema 5). vault_lint runs
  aging-inbox + scope-drift per member. migrate.py 4->5 for alpha vaults.
- Scaffold: member-* seeds ({{MEMBER}}-stamped), group-profile/group-inbox
  seeds, marker schema 5. Docs (SKILL, vault-layout, routing-map,
  bootstrap) synced; manifest -> 2.0.0-alpha.3; rebuilt plugin (81 files).

Verified: all suites green (25/25 unit, scaffold, routing-sync 36 routes,
4 mock e2e, run_eval unchanged) + 19-check two-member smoke: bootstrap ->
self-onboard -> interleaved tagged daily log -> cross-member update
attribution -> independent scopes -> mine/group triage -> lint clean.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

CHANGELOG.md

@@ -1,5 +1,52 @@
 # Changelog
 
+## 2.0.0-alpha.3 — Phase 3 (per-member namespacing — schema 5)
+
+The core of the group conversion: one shared vault, per-member namespaces for all
+churn-prone state. A CHORUS vault now bootstraps multi-member from empty.
+
+### Added — vault layout (schema 5)
+- **`_agent/members/<member>/`** — each member's `preferences.md`,
+  `current-context.md` (scope + history), `heartbeat.md` (last-session pointer,
+  written at session end), and `inbox.md`. Members never contend on each other's
+  churn-prone files.
+- **`_agent/sessions/<member>/YYYY-MM-DD-HHMM-<slug>.md`** — member-namespaced
+  session logs (no same-minute collisions, filterable per member).
+- **`_agent/memory/semantic/group-profile.md`** — shared group facts, conventions,
+  and a `## Members` roster (members are rostered automatically at onboarding).
+- **`inbox/captures/group.md`** — shared inbox for unowned member-tagged items;
+  whoever triages first routes them.
+
+### Added — behavior
+- **Self-onboarding**: `chorus.py load` detects a bootstrapped vault that lacks THIS
+  member's namespace and stands it up automatically (anchors + sessions dir +
+  roster line). New members install their baked plugin and just start.
+- `load` is now 8 orientation reads: marker → group profile → my preferences /
+  context / heartbeat → today's shared daily note → my inbox → group inbox; the
+  heartbeat fallback lists MY sessions dir.
+- `scope show/set` operates on the member's own current-context; drift counts only
+  that member's sessions.
+- **Member-tagged shared writes**: daily `## Agent Log` lines and entity-update
+  dated blocks are written as `- YYYY-MM-DD [member]: …`; `capture --inbox` lands
+  in the member's own inbox; triage lists BOTH inboxes (tagged mine/group) and
+  writes member-attributed audit lines.
+- `bootstrap.py` seeds group anchors + the configured member's namespace
+  (`member_bootstrap()` is reusable); the marker is schema 5; `migrate.py` gains a
+  4→5 step for alpha vaults (moves pre-5 anchors into the configured member's
+  namespace; no ECHO adoption path).
+- `routing.json`: new `member-anchors`, `inbox-group`, member-segmented sessions
+  routes; the old single-user anchor paths (shared inbox, operator-preferences,
+  current-context, heartbeat, flat sessions) are **retired**. `vault_lint` runs
+  aging-inbox and scope-drift checks per member across all members found in the
+  vault. Docs (SKILL, vault-layout, routing-map, bootstrap) updated to match.
+
+### Verified
+- All suites green (25/25 unit, scaffold, routing-sync ×36 routes, 4 mock e2e,
+  run_eval metrics unchanged) plus a 19-check two-member end-to-end smoke:
+  jason bootstraps → alice self-onboards via load → interleaved member-tagged
+  daily log → cross-member entity update attributed → independent scopes →
+  triage separates personal vs group items → lint clean.
+
 ## 2.0.0-alpha.2 — Phase 2 (identity plumbing)
 
 Every write is now attributed to a member. Vault layout unchanged (that's Phase 3).