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diff --git a/‎packages/core/src/fallbacks/authored-translation-sync.test.ts‎
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@@ -66,8 +66,9 @@ and the rejection carries the prescription above.
 
 ### Unchanged
 
-The registered `translation` metadata type (`TranslationItemSchema`) still
-declares `settings` — this ruling covers the file-authored bundle. `GET
+The registered `translation` metadata type (`TranslationItemSchema`) is not
+changed by THIS entry — this ruling covers the file-authored bundle. (Superseded
+in the same release: #19620 narrows the item door too; see its own changeset.) `GET
 /api/v1/i18n/translations/:locale` still declares it on its response, because the
 served document is the merged tree; `GetTranslationsResponseSchema` is typed
 against the platform face for exactly that reason.
 
@@ -0,0 +1,71 @@
+---
+'@objectstack/spec': minor
+'@objectstack/core': minor
+---
+
+**BREAKING for runtime-authored `translation` items** — the registered `translation` metadata type no longer declares `settings`: platform settings copy is platform-only at BOTH application doors (#19620)
+
+Clause-②: no
+
+`TranslationItemSchema` — one `translation` metadata item, authored with
+`defineTranslation`, in Studio, or through the metadata API — now takes the same
+ten groups as a per-app bundle entry (`TranslationData`). `settings`, and its
+singular `setting`, are refused by name with the platform-only prescription,
+exactly as the per-app bundle has refused them since #15178. The file door and
+the item door are two authoring surfaces for one app metadata type, so they
+accept one shape.
+
+### Migration — FROM → TO
+
+| You wrote | Write instead |
+| --- | --- |
+| `defineTranslation({ locale: 'zh-CN', settings: { mail: { title: '邮件投递' } } })` | delete the `settings` group — there is no application-side replacement key |
+| a `translation` item saved through the metadata API or Studio carrying `settings` | delete the `settings` group; the save answers `422 INVALID_METADATA` until you do |
+| `const t: TranslationItem = { locale: 'en', settings: … }` | move the copy to the PLATFORM bundle (`PlatformTranslationData`), or delete it |
+
+**The one-line fix: delete the `settings` group from the item.** Settings copy is
+not application-authorable — `settings` is keyed by `SettingsManifest.namespace`
+and only platform code declares a manifest. `settingsCommon` is **not** affected:
+the Settings UI shell strings (the source badges, under
+`settingsCommon.sourceLabels`) stay on both application faces.
+Run `os migrate meta --from 17` to list the mechanical edits for existing
+sources; apply them by hand.
+
+### Rows already stored are converted, not refused
+
+A `translation` row saved before this change keeps loading. The runtime
+translation sync (`@objectstack/core`'s `authored-translation-sync`) reads
+`sys_metadata` itself and used to merge the RAW stored payload; it now replays
+the ADR-0087 conversion chain over each row before merging it, the same policy
+as every other stored-metadata read seam. `translation-per-app-settings-removed`
+has learned the item shape, so a stored row's `settings` is dropped there, the
+rest of the item (`objects`, `apps`, …) still loads, and the server logs one
+warning per row naming the row, the group and the conversion. Run
+`os migrate meta --stored --apply` to persist the canonical rows.
+
+### What changes on screen, which is not nothing
+
+On the item door the group was STRONGER than on the bundle door. A published
+item is loaded into the runtime-authored layer, which both i18n adapters read
+**over** the shipped bundles — so an item's `settings` overrode the platform's
+own Settings copy for its locale, rather than only filling gaps. After
+upgrading, re-read the Settings screens in each locale such an item covered:
+where it overrode a platform string, **the platform's string renders again**;
+where it filled a gap the platform bundle leaves, the **manifest's own literal
+renders, which is English**. If a platform string is wrong or missing for your
+locale, correct it in the platform bundle (`@objectstack/service-settings`'s
+`settingsBuiltinTranslations`).
+
+No deprecation window: the item door refuses the key by name from this major.
+
+### Unchanged
+
+The platform face — `PlatformTranslationDataSchema`, `settingsBuiltinTranslations`,
+and `GET /api/v1/i18n/translations/:locale`, whose served document is the merged
+tree — still declares `settings`. The liveness ledger's `translation.settings`
+row is deleted because the key left the ITEM's shape; the platform capability it
+evidenced is untouched.
+
+Ruling batch #210 item 2 letter B (2026-09-22) — maintainer 「210 同意」.
+
+<!-- adr-0087: not-required (already-registered translation-per-app-settings-removed, translation-per-app-settings-platform-only) both entries already existed for the per-app bundle door; this change EXTENDS them to the translation item door in the same unreleased major — the D2 conversion learns the bare item shape and the D3 semantic entry covers both doors -->
@@ -406,7 +406,9 @@ Three rules the shape enforces, all of them closed since #4001:
   it.** It is keyed by `SettingsManifest.namespace`, and only platform code
   declares a manifest — so the only namespaces an application could ever
   address are the platform's own. Writing it in `stack.translations` (or in
-  `defineTranslationBundle`) is refused by name with that prescription; the
+  `defineTranslationBundle`) is refused by name with that prescription, and so
+  is writing it on a `translation` metadata item (`defineTranslation`, or a save
+  through the metadata API) — the item door takes the same per-app face; the
   platform's own bundles author it against `PlatformTranslationData`, and the
   served document (`GET /i18n/translations/:locale`) carries it because it is
   the merge of every loaded bundle.
 
@@ -506,7 +506,6 @@ One locale of translations — the `translation` metadata type
 | **flows** | `Record<string, { label?: string; screens?: Record<string, object> }>` | optional | Screen-flow translations keyed by flow name |
 | **metadataForms** | `Record<string, { label?: string; description?: string; sections?: Record<string, object>; fields?: Record<string, object> }>` | optional | Translations for metadata-type configuration forms keyed by metadata type |
 | **settingsCommon** | `{ sourceLabels?: object }` | optional | Cross-namespace Settings UI strings |
-| **settings** | `Record<string, { title?: string; description?: string; groups?: Record<string, object>; keys?: Record<string, object>; … }>` | optional | Settings manifest translations keyed by namespace |
 | **locale** | `string` | ✅ | BCP-47 locale this item translates (e.g. "zh-CN") |
 | **name** | `string` | optional | Item name — conventionally the locale code (`zh-CN`); the runtime sync falls back to it when `locale` is absent |
 | **label** | `string` | optional | Human-readable label shown in metadata lists |
@@ -604,16 +603,6 @@ Translation data for a single object
 | :--- | :--- | :--- | :--- |
 | **sourceLabels** | `{ env?: string; global?: string; tenant?: string; user?: string; … }` | optional | Source badge labels by resolution layer |
 
-### Nested Shape: `TranslationItem.settings[string]`
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **title** | `string` | optional | Translated settings manifest title |
-| **description** | `string` | optional | Translated settings manifest description |
-| **groups** | `Record<string, { title?: string; description?: string }>` | optional | Group translations keyed by group key |
-| **keys** | `Record<string, { label?: string; help?: string; placeholder?: string; options?: Record<string, string> }>` | optional | Per-setting field translations keyed by setting key |
-| **actions** | `Record<string, { label?: string; confirmText?: string; successMessage?: string }>` | optional | Action button translations keyed by action id |
-
 
 ---
 
@@ -217,11 +217,13 @@ Two things to know:
   a silent skip is the hardest kind of missing translation to diagnose.
 - Only the groups on this page are accepted, and since #4001 that is literally
   true: a key none of them declares is rejected, in a runtime item **and** in a
-  file-authored bundle. One group differs between the two doors: `settings` is
-  **platform-only** — a file bundle refuses it by name, and although the
-  registered `translation` item still declares it, the only namespaces it can
-  address are the platform's own, because only platform code declares a settings
-  manifest. Keys from the retired `o.<object>` shape (`o`, `app`,
+  file-authored bundle. `settings` is **platform-only** and both doors refuse it
+  by name: it is keyed by a settings manifest's namespace, and only platform code
+  declares a manifest, so the only namespaces it could address are the platform's
+  own. On a runtime item it used to be accepted — and because published items
+  layer over the shipped bundles, it overrode the platform's own Settings copy. A
+  row stored with it before the door closed loads without that group, with a
+  warning in the server log. Keys from the retired `o.<object>` shape (`o`, `app`,
   `nav`, `dashboard`, `_globalOptions`, `_meta`, …) carry a message naming the
   group to use instead — they used to save cleanly and then render nothing
   (#3778). Everything else gets the nearest declared key suggested.
 
@@ -299,7 +299,7 @@
       ],
       "traps": ["stale-console-bundle", "hydration-race", "wrong-panel", "dispatcher-vs-hono-route"],
       "source": [
-        "packages/spec/src/system/translation.zod.ts#appTranslationDataShape (appTranslationDataShape — the group vocabulary an APPLICATION may author: objects/_views/_actions/_sections, apps.navigation, messages, globalActions, dashboards, datasets, pages, flows, metadataForms, settingsCommon. `settings` is platform-only since #15178 and lives in platformSettingsShape, spread into PlatformTranslationDataSchema and TranslationItemSchema)",
+        "packages/spec/src/system/translation.zod.ts#appTranslationDataShape (appTranslationDataShape — the group vocabulary an APPLICATION may author: objects/_views/_actions/_sections, apps.navigation, messages, globalActions, dashboards, datasets, pages, flows, metadataForms, settingsCommon. `settings` is platform-only since #15178 and lives in platformSettingsShape, spread into PlatformTranslationDataSchema only — TranslationItemSchema refuses it too since #19620)",
         "examples/app-showcase/src/system/translations/index.ts (full-column coverage rationale)",
         "packages/services/service-i18n/src/i18n-service-plugin.ts#i18n (GET /i18n/locales | /translations/:locale | /labels/:object/:locale; { success, data } envelope #3636/#3675; resolveObjectFieldLabels nested shape #3778/#3833; the plugin mount and the dispatcher /i18n domain serve the same routes interchangeably)",
         "packages/services/service-i18n/src/file-i18n-adapter.ts#getLocales (getLocales / getTranslations — unloaded locale → {}; fallbackLocale applies per-KEY in t(), not to the bulk route)",
 
@@ -0,0 +1,120 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * #19620 — the stored-row half of retiring `settings` from the `translation`
+ * item door (ruling batch #210 item 2 letter B).
+ *
+ * Narrowing `TranslationItemSchema` refuses NEW items carrying `settings` at
+ * the metadata door, but it cannot reach a row already stored: this sync reads
+ * `sys_metadata` itself and used to merge the RAW payload into the authored
+ * layer, which both i18n adapters read OVER the shipped bundles. So a row
+ * written before the door closed kept overriding the platform's own Settings
+ * copy on every boot. The sync is a rehydration seam and now replays the
+ * ADR-0087 chain over each row before merging it, which is what drops the
+ * group — loudly, once per row.
+ *
+ * `@objectstack/spec` resolves to its BUILT `dist/` here (no alias), and the
+ * conversion that does the dropping lives there: rebuild spec before reading
+ * a result from this file.
+ */
+
+import { describe, expect, it, vi } from 'vitest';
+
+import { readAuthoredTranslationLayer, wireAuthoredTranslationSync } from './authored-translation-sync.js';
+import { createMemoryI18n } from './memory-i18n.js';
+
+type AnyRecord = Record<string, any>;
+
+const row = (name: string, payload: AnyRecord) => ({
+  type: 'translation',
+  name,
+  state: 'active',
+  metadata: JSON.stringify(payload),
+});
+
+const engineOf = (rows: AnyRecord[]) => ({
+  find: vi.fn(async (_object: string, q: AnyRecord) => (q?.where?.type === 'translation' ? rows : [])),
+});
+
+/** An item stored before the door closed: `settings` beside an app-owned group. */
+const storedWithSettings = () => row('zh-CN', {
+  locale: 'zh-CN',
+  settings: { mail: { title: '应用改写的邮件标题', keys: { host: { label: '应用改写的主机' } } } },
+  apps: { crm: { label: '客户关系管理' } },
+});
+
+describe('authored-translation sync replays the conversion chain over stored rows (#19620)', () => {
+  it('drops a stored item\'s `settings` before the merge and keeps the rest of the item', async () => {
+    const warn = vi.fn();
+    const layer = await readAuthoredTranslationLayer(engineOf([storedWithSettings()]), { warn });
+
+    expect(layer).not.toBeNull();
+    expect(layer!['zh-CN']).not.toHaveProperty('settings');
+    // The app-owned group on the same row still loads — the row is converted,
+    // not skipped.
+    expect(layer!['zh-CN']).toEqual({ apps: { crm: { label: '客户关系管理' } } });
+  });
+
+  it('says so, naming the row, the group and the conversion — never a silent strip', async () => {
+    const warn = vi.fn();
+    await readAuthoredTranslationLayer(engineOf([storedWithSettings()]), { warn });
+
+    expect(warn).toHaveBeenCalledTimes(1);
+    const line = String(warn.mock.calls[0]?.[0]);
+    expect(line).toContain("authored translation 'zh-CN'");
+    expect(line).toContain("'settings' → '(removed)'");
+    expect(line).toContain("'translation-per-app-settings-removed'");
+    expect(line).toContain('os migrate meta --stored --apply');
+  });
+
+  it('warns once per row per wiring, not on every sync', async () => {
+    const warn = vi.fn();
+    const warnedConversions = new Set<string>();
+    const engine = engineOf([storedWithSettings()]);
+    await readAuthoredTranslationLayer(engine, { warn }, { warnedConversions });
+    await readAuthoredTranslationLayer(engine, { warn }, { warnedConversions });
+
+    expect(warn).toHaveBeenCalledTimes(1);
+  });
+
+  it('CONTROL — a canonical row converts to itself and warns nothing', async () => {
+    const warn = vi.fn();
+    const layer = await readAuthoredTranslationLayer(
+      engineOf([row('zh-CN', { locale: 'zh-CN', apps: { crm: { label: '客户关系管理' } } })]),
+      { warn },
+    );
+
+    expect(layer!['zh-CN']).toEqual({ apps: { crm: { label: '客户关系管理' } } });
+    expect(warn).not.toHaveBeenCalled();
+  });
+
+  it('end to end: the platform\'s own settings copy renders again, not the stored override', async () => {
+    // The platform bundle as `SettingsServicePlugin` contributes it — static.
+    const i18n = createMemoryI18n();
+    i18n.loadTranslations('zh-CN', {
+      settings: { mail: { title: '邮件投递', keys: { host: { label: 'SMTP 主机' } } } },
+    });
+
+    const hooks = new Map<string, Array<() => Promise<void> | void>>();
+    const warn = vi.fn();
+    const services: AnyRecord = { i18n, objectql: engineOf([storedWithSettings()]) };
+    wireAuthoredTranslationSync({
+      logger: { warn, info: vi.fn(), debug: vi.fn() },
+      getService: (name: string) => {
+        if (name in services) return services[name];
+        throw new Error(`service '${name}' not registered`);
+      },
+      hook: (name, fn) => hooks.set(name, [...(hooks.get(name) ?? []), fn]),
+    });
+    for (const fn of hooks.get('kernel:ready') ?? []) await fn();
+    for (const fn of hooks.get('metadata:reloaded') ?? []) await fn();
+
+    // Before the seam replayed the chain, the authored layer (read OVER the
+    // static bundle) answered these two with the stored row's strings.
+    expect(i18n.t('settings.mail.title', 'zh-CN')).toBe('邮件投递');
+    expect(i18n.t('settings.mail.keys.host.label', 'zh-CN')).toBe('SMTP 主机');
+    expect(i18n.t('apps.crm.label', 'zh-CN')).toBe('客户关系管理');
+    // Two syncs, one warning: the wiring owns its dedupe set.
+    expect(warn).toHaveBeenCalledTimes(1);
+  });
+});