docs(STATE-WP-0079): execute slice E2, retire 15 legacy interfaces

Retires the 15 workstream->workplan aliases that meet the retirement
standard: verified replacement, no manual hold, zero calls in a 7-day
window, and silence past the volume-scaled quiet threshold. Meter now reads
16 retired / 4 legacy with 0 outstanding candidates.

The 4 held are the three six-figure read paths and GET /tasks/?workstream_id
which still has traffic -- the set where a premature retirement would do the
most damage. They clear as their quiet counters run.

Journalled fleet-side in the-custodian/docs/retired-legacy-interfaces.md so
the record outlives this repo's archive.

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

docs/retirement-cutover-slice-plan.md

@@ -242,7 +242,9 @@ the low-volume REST aliases, plus `PATCH /workstreams/{id}` (571 calls, quiet
 | `GET /workstreams/{id}` | 511 406 | quiet 19d of 60d |
 | `GET /workstreams/{id}/dependencies/` | 255 865 | quiet 42d of 60d |
 
-E2 can therefore proceed for the 15, which is the bulk of the slice. The four
+**Executed 2026-08-20:** the 15 are retired; the meter reads 16 retired / 4
+legacy with 0 outstanding candidates. Journalled at
+`the-custodian/docs/retired-legacy-interfaces.md`. The four
 held are the three six-figure read paths and the one with live traffic — exactly
 the set where a false retirement would hurt most. They clear on their own as the
 quiet counter runs, provided no new traffic arrives; the earliest,

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

@@ -163,10 +163,24 @@ read paths (`GET /workstreams/`, `GET /workstreams/{id}`,
 `GET /workstreams/{id}/dependencies/`) and `GET /tasks/?workstream_id`, which
 still has live traffic. Covered by 7 new tests in `tests/test_legacy_meter.py`.
 
-**Remaining work for this task:** execute the retirement of the 15 evidenced
+**Slice E2 executed (2026-08-20):** the 15 evidenced interfaces are retired in
-interfaces, then re-review the 4 held ones as their quiet counters run. The
+the legacy meter — all four `workstream` MCP tools, the `state://` resource, and
-ladder is evaluated at review time, so re-capture before deciding. See
+the low-volume REST aliases including `PATCH /workstreams/{id}` (571 calls),
-`docs/retirement-cutover-slice-plan.md` § E2.
+`POST /workstreams/` (824) and `POST /workstreams/{id}/dependencies/` (4 971).
+Meter now reads 16 retired / 4 legacy, 0 outstanding candidates. Evidence:
+`docs/evidence/legacy-meter-weekly-review-20260820.json`.
+
+Retirements are journalled fleet-side at
+`the-custodian/docs/retired-legacy-interfaces.md` — deliberately outside this
+repo, since State Hub is being archived and the record must outlive it.
+
+**Remaining work for this task:** the 4 held interfaces
+(`GET /workstreams/`, `GET /workstreams/{id}`,
+`GET /workstreams/{id}/dependencies/`, `GET /tasks/?workstream_id`) clear as
+their quiet counters run; earliest is 18 more silent days. Re-capture before
+deciding — the ladder evaluates at review time. Then the remaining `retire`
+inventory items outside E2: `suggestion-backlog` (E1, 17) and `dashboard-meta`
+(E3, 1); `legacy-meter` itself (E4, 9) retires last, being the instrument.
 
 ## Stabilization window and archive prep