docs(STATE-WP-0079): A2a executed, dual-run live for repo-manager pilot

First live cutover slice. Installed the shipped pilot config (writeback and
reconcile on, writeback_push off, scoped to repo-manager), reloaded the API
via its own --reload watcher rather than restarting the operator's process,
and confirmed reconcile routed through rmgr with a new mutation meter entry
(8 workplans, 53 tasks, 61 records).

Divergence check clean: the one-workplan delta against the hub is
RMGR-WP-0008, unregistered because this instance is not the identifier
registrar, not a dual-run divergence.

Slice sits at dual, not owner -- the hub stays authoritative until a full
sweep cycle shows zero divergence.

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

workplans/STATE-WP-0079-retirement-strangler.md

@@ -160,6 +160,30 @@ it changes how live task writes flow.
 Net: of 425 inventory items, roughly **6 can move today**. The retirement is
 gated almost entirely on owner-side capability in `repo-manager` and `hub-core`.
 
+**A2a executed (2026-08-20) — first live cutover slice.** Dual-run is on for the
+pilot repo:
+
+- `~/.repo-manager/dual-run.yaml` installed from
+  `repo-manager/config/dual-run.pilot.example.yaml` — `writeback: true`,
+  `reconcile: true`, `writeback_push: false`, `pilot_repos: [repo-manager]`
+- State Hub API reloaded via its own `--reload` watcher (no service restart, the
+  operator's foreground `make api` was left alone)
+- `statehub fix-consistency --repo repo-manager` reported
+  `RM dual-run reconcile ok: index=/home/worsch/repo-manager/.repo-manager/index.json`
+- mutation meter grew 23 → 24 with
+  `{"kind": "reconcile", "repo_slug": "repo-manager", "workplan_count": 8, "task_count": 53, "record_count": 61}`
+
+**Divergence check:** rmgr's index holds 8 workplans; the hub has
+`rmgr-wp-0001`–`0007` registered. The single-item delta is `RMGR-WP-0008`, whose
+C-06 registration was skipped because this instance is not the identifier
+registrar (ADR-007 interim). That is a known registrar limitation, **not**
+dual-run divergence — rmgr correctly indexed the file that exists on disk.
+
+Slice state: **A2a is `dual`, not `owner`** — the hub remains authoritative and
+rmgr executes checkout mutation alongside it. Promotion to `owner` needs a full
+consistency-sweep cycle at `dual` with zero divergence, per this plan's adapter
+rules. Rollback is `rm ~/.repo-manager/dual-run.yaml`.
+
 **Inherited (2026-08-19) from `STATE-WP-0080-T04`:** this slice now also owns
 deletion of the templating path in `statehub_register.py` — `INTENT.md`
 generation, the `AGENTS.md` / `CLAUDE.md` / `.custodian-brief.md` templates,