@@ -0,0 +1,10 @@
+---
+'@object-ui/i18n': patch
+---
+
+feat(i18n): the Studio inspectors' page block, action, dataset, flow node, app navigation and dashboard widget strings move into the `studio` namespace
+
+Clause-②: no
+Metadata-protocol: none
+
+- **Second slice of the move ruled on objectstack#25922** (6431032267, Q2 = A; kept by 6431234244). The 520 keys under `engine.inspector.pageBlock.*`, `engine.inspector.action.*`, `engine.inspector.dataset.*`, `engine.inspector.flowNode.*`, `engine.inspector.appNav.*` and `engine.inspector.widget.*` now live in `@object-ui/i18n/namespaces/studio` instead of `@object-ui/app-shell`'s private table, text unchanged in both `en` and `zh`. Studio reads the same strings; a Chinese viewer sees these labels in English for the moment the `zh` catalogue takes to load, as with the first slice. No export changes.
@@ -31,6 +31,11 @@ vi.mock('../previews/useDatasetCatalog', () => ({
 }));
 
 import { DashboardWidgetInspector } from './DashboardWidgetInspector';
+// The inspector's `engine.inspector.*` rows live in `@object-ui/i18n`'s `studio`
+// namespace, whose `zh` catalogue is fetched on demand (objectstack#25922).
+// Resident before any case, so the zh rows below read synchronously.
+import { loadStudioCatalogue } from '@object-ui/i18n/namespaces/studio';
+await loadStudioCatalogue('zh');
 
 afterEach(cleanup);
 
 
@@ -80,6 +80,11 @@ import { registerDefaultMetadataSchemas } from '../default-schemas';
 import { registerBuiltinPreviews } from '../previews';
 import { registerBuiltinInspectors } from '.';
 import { DatasetDefaultInspector, objectChangePatch } from './DatasetDefaultInspector';
+// The inspector's `engine.inspector.*` rows live in `@object-ui/i18n`'s `studio`
+// namespace, whose `zh` catalogue is fetched on demand (objectstack#25922).
+// Resident before any case, so the zh rows below read synchronously.
+import { loadStudioCatalogue } from '@object-ui/i18n/namespaces/studio';
+await loadStudioCatalogue('zh');
 
 const DATASET_JSON_SCHEMA = z.toJSONSchema(getMetadataTypeSchema('dataset') as z.ZodType, {
   io: 'input',
 
@@ -31,6 +31,11 @@ import { FlowNodeInspector } from './FlowNodeInspector';
 import { encodeNestedNodeId } from './flow-nested-selection';
 import { t, tFormat, type SupportedLocale } from '../i18n';
 import type { MetadataSelection } from '../preview-registry';
+// The inspector's `engine.inspector.*` rows live in `@object-ui/i18n`'s `studio`
+// namespace, whose `zh` catalogue is fetched on demand (objectstack#25922).
+// Resident before any case, so the zh rows below read synchronously.
+import { loadStudioCatalogue } from '@object-ui/i18n/namespaces/studio';
+await loadStudioCatalogue('zh');
 
 afterEach(cleanup);
 
 
@@ -45,6 +45,11 @@ const state = vi.hoisted(() => ({
 vi.mock('../useMetadata', () => ({ useMetadataClient: () => state.metadataClient }));
 
 import { PageBlockInspector } from './PageBlockInspector';
+// The inspector's `engine.inspector.*` rows live in `@object-ui/i18n`'s `studio`
+// namespace, whose `zh` catalogue is fetched on demand (objectstack#25922).
+// Resident before any case, so the zh rows below read synchronously.
+import { loadStudioCatalogue } from '@object-ui/i18n/namespaces/studio';
+await loadStudioCatalogue('zh');
 
 afterEach(cleanup);
 
 
@@ -48,6 +48,11 @@ vi.mock('../useMetadata', () => ({
 }));
 
 import { PageBlockInspector } from './PageBlockInspector';
+// The inspector's `engine.inspector.*` rows live in `@object-ui/i18n`'s `studio`
+// namespace, whose `zh` catalogue is fetched on demand (objectstack#25922).
+// Resident before any case, so the zh rows below read synchronously.
+import { loadStudioCatalogue } from '@object-ui/i18n/namespaces/studio';
+await loadStudioCatalogue('zh');
 
 afterEach(cleanup);
 
 
@@ -41,6 +41,11 @@ vi.mock('../useMetadata', () => ({
 }));
 
 import { PageBlockInspector } from './PageBlockInspector';
+// The inspector's `engine.inspector.*` rows live in `@object-ui/i18n`'s `studio`
+// namespace, whose `zh` catalogue is fetched on demand (objectstack#25922).
+// Resident before any case, so the zh rows below read synchronously.
+import { loadStudioCatalogue } from '@object-ui/i18n/namespaces/studio';
+await loadStudioCatalogue('zh');
 
 afterEach(cleanup);
 
 
@@ -34,6 +34,11 @@ import { SchemaRenderer, PredicateScopeProvider } from '@object-ui/react';
 import { PageBlockInspector } from './PageBlockInspector';
 import type { MetadataInspectorProps } from '../inspector-registry';
 import type { SupportedLocale } from '../i18n';
+// The inspector's `engine.inspector.*` rows live in `@object-ui/i18n`'s `studio`
+// namespace, whose `zh` catalogue is fetched on demand (objectstack#25922).
+// Resident before any case, so the zh rows below read synchronously.
+import { loadStudioCatalogue } from '@object-ui/i18n/namespaces/studio';
+await loadStudioCatalogue('zh');
 
 afterEach(cleanup);
 
 
@@ -0,0 +1,62 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * objectstack#25922 slice S2 — the page block, action, dataset, flow node, app
+ * navigation and dashboard widget inspector rows (`engine.inspector.{pageBlock,
+ * action,dataset,flowNode,appNav,widget}.*`) live in `@object-ui/i18n`'s
+ * `studio` namespace, and app-shell's `t()` still answers every one of them the
+ * way it did when they sat in its own table.
+ *
+ * What would break it:
+ *   - a row copied back into the app-shell table with a different value — the
+ *     table is asked first, so it would shadow the namespace silently;
+ *   - the namespace fallback dropped from `lookupString` — every moved key
+ *     would echo back as itself;
+ *   - a family emptied out of the namespace, which every per-key assertion
+ *     below would then pass over nothing. The floors are per FAMILY, by name,
+ *     so one family draining cannot hide behind another one growing.
+ *
+ * The oracle is the namespace's own catalogues, read through
+ * `loadStudioCatalogue` (the module's public door), not a copy of their text.
+ */
+import { describe, expect, it } from 'vitest';
+import { loadStudioCatalogue } from '@object-ui/i18n/namespaces/studio';
+import { t } from '../i18n';
+
+const EN = await loadStudioCatalogue('en');
+// Resident before any case, so the zh lookups below read synchronously.
+const ZH = await loadStudioCatalogue('zh');
+
+/** Family → the fewest keys it may carry (measured at the move, rounded down). */
+const S2_FAMILY_FLOOR: Readonly<Record<string, number>> = Object.freeze({
+  pageBlock: 160,
+  action: 120,
+  dataset: 80,
+  flowNode: 40,
+  appNav: 40,
+  widget: 40,
+});
+
+const familyKeys = (family: string): string[] =>
+  Object.keys(EN).filter((key) => key.startsWith(`engine.inspector.${family}.`));
+
+describe('S2 inspector rows answer from the studio namespace (objectstack#25922)', () => {
+  it.each(Object.entries(S2_FAMILY_FLOOR))('%s: the namespace carries the family, in en and zh', (family, floor) => {
+    const keys = familyKeys(family);
+    expect(keys.length).toBeGreaterThanOrEqual(floor);
+    expect(keys.filter((key) => !(key in ZH))).toEqual([]);
+  });
+
+  it.each(Object.keys(S2_FAMILY_FLOOR))('%s: t() answers every key with the namespace value', (family) => {
+    const wrong = familyKeys(family).flatMap((key) => {
+      const out: string[] = [];
+      if (t(key, 'en-US') !== EN[key]) out.push(`en-US ${key}: ${t(key, 'en-US')}`);
+      if (t(key, 'zh-CN') !== ZH[key]) out.push(`zh-CN ${key}: ${t(key, 'zh-CN')}`);
+      // A language the namespace has no catalogue for reads English, as it did
+      // from the app-shell table.
+      if (t(key, 'de-DE') !== EN[key]) out.push(`de-DE ${key}: ${t(key, 'de-DE')}`);
+      return out;
+    });
+    expect(wrong).toEqual([]);
+  });
+});
@@ -80,6 +80,11 @@ import path from 'node:path';
 import { BLOCK_CONFIG, type BlockPropField, type PlaceholderSpec } from '../block-config';
 import { t } from '../../i18n';
 import { uiRoot } from '../../../../../../../scripts/ui-root.mjs';
+// `engine.inspector.pageBlock.*` lives in `@object-ui/i18n`'s `studio`
+// namespace, whose `zh` catalogue is fetched on demand (objectstack#25922).
+// Resident before any case, so the zh rows below read synchronously.
+import { loadStudioCatalogue } from '@object-ui/i18n/namespaces/studio';
+await loadStudioCatalogue('zh');
 
 const PREFIX = 'engine.inspector.pageBlock';
 
@@ -474,7 +479,8 @@ describe('placeholders that must NOT be translated (#3979)', () => {
  * must LEAVE both tables — and until this describe nothing measured it. The two
  * repo-wide i18n gates cannot: `check:i18n-keys` and `check:i18n-dead-keys`
  * both read `packages/i18n/src/locales/`, and `engine.inspector.pageBlock.*`
- * lives only in `metadata-admin/i18n.ts` (which says so in its own header). So
+ * lives only in the designer strings (the `studio` namespace since
+ * objectstack#25922; `metadata-admin/i18n.ts` says so in its own header). So
  * each of the four renames so far (objectui#3829, objectui#5212, objectui#8279,
  * objectui#8278) shipped with a HAND-WRITTEN pin naming the one key it retired
  * — a convention, not an instrument, and the fifth rename is one forgotten pin
@@ -498,6 +504,11 @@ describe('placeholders that must NOT be translated (#3979)', () => {
  *      of the source, the same way `PageBlockInspector.i18n.test.tsx` reads its
  *      own chrome key list rather than hand-copying it.
  *
+ * Since objectstack#25922 slice S2 the prefix lives in the `studio` namespace
+ * of `@object-ui/i18n` (`packages/i18n/src/namespaces/studio/{en,zh}.ts`), so
+ * a locale's key set is read from BOTH homes — the app-shell table and the
+ * namespace catalogue — and a key is retired only when it has left both.
+ *
  * Measured on this checkout: every one of the 171 `engine.inspector.pageBlock.*`
  * keys in each table is covered by one of those two, and no key is constructed
  * dynamically anywhere (`grep` for a template head under this prefix returns
@@ -540,6 +551,11 @@ const I18N_SOURCE_PATH = path.join(
   ROOT,
   'packages/app-shell/src/views/metadata-admin/i18n.ts',
 );
+/** The `studio` namespace's catalogues — the prefix's home since objectstack#25922 S2. */
+const STUDIO_HOME_PATH = {
+  en: path.join(ROOT, 'packages/i18n/src/namespaces/studio/en.ts'),
+  zh: path.join(ROOT, 'packages/i18n/src/namespaces/studio/zh.ts'),
+};
 
 interface EngineStringTable {
   /** The `const` name, for assertion messages. */
@@ -565,7 +581,7 @@ interface EngineStringTable {
 function engineStringTable(source: string, name: string): EngineStringTable {
   const lines = source.split('\n');
   const open = lines.findIndex((l) => l.startsWith(`const ${name}: Record<string, string> = {`));
-  if (open === -1) throw new Error(`${name}: declaration not found in i18n.ts — the extractor is stale`);
+  if (open === -1) throw new Error(`${name}: declaration not found — the extractor is stale`);
   const close = lines.findIndex((l, i) => i > open && l === '};');
   if (close === -1) throw new Error(`${name}: no column-0 '};' closes the table — the extractor is stale`);
   const keys: string[] = [];
@@ -602,6 +618,7 @@ function shippedLiteralKeys(): Map<string, string[]> {
       if (!/\.(ts|tsx|js|jsx|mjs)$/.test(entry.name)) continue;
       if (/\.(test|spec)\.[tj]sx?$/.test(entry.name)) continue;
       if (full === I18N_SOURCE_PATH) continue; // the DEFINITION site, not a reader
+      if (full === STUDIO_HOME_PATH.en || full === STUDIO_HOME_PATH.zh) continue; // likewise
       const content = readFileSync(full, 'utf8');
       if (!content.includes(PREFIX)) continue;
       for (const m of content.matchAll(/['"`](engine\.inspector\.pageBlock\.[A-Za-z0-9_.:$-]+)['"`]/g)) {
@@ -619,6 +636,15 @@ function shippedLiteralKeys(): Map<string, string[]> {
 const I18N_SOURCE = readFileSync(I18N_SOURCE_PATH, 'utf8');
 const EN_TABLE = engineStringTable(I18N_SOURCE, 'ENGINE_STRINGS_EN');
 const ZH_TABLE = engineStringTable(I18N_SOURCE, 'ENGINE_STRINGS_ZH');
+const EN_HOME = engineStringTable(readFileSync(STUDIO_HOME_PATH.en, 'utf8'), 'STUDIO_EN');
+const ZH_HOME = engineStringTable(readFileSync(STUDIO_HOME_PATH.zh, 'utf8'), 'STUDIO_ZH');
+
+/** One locale's keys across both homes: the app-shell table and the namespace. */
+function bothHomes(table: EngineStringTable, home: EngineStringTable): EngineStringTable {
+  return { name: `${table.name} + ${home.name}`, keys: [...table.keys, ...home.keys], from: table.from, to: table.to };
+}
+const EN_KEYS = bothHomes(EN_TABLE, EN_HOME);
+const ZH_KEYS = bothHomes(ZH_TABLE, ZH_HOME);
 
 /** The keys `SITES` implies — the complete BLOCK_CONFIG-derived vocabulary. */
 const DERIVED = new Set(SITES.map((s) => s.derived));
@@ -656,15 +682,21 @@ describe('a retired key leaves BOTH locale tables (objectui#8368)', () => {
     // set arithmetic below would hide it.
     expect(EN_TABLE.keys.length).toBe(new Set(EN_TABLE.keys).size);
     expect(ZH_TABLE.keys.length).toBe(new Set(ZH_TABLE.keys).size);
+    // The namespace homes are read the same way, and a key in both homes of
+    // one locale would be counted twice below.
+    expect(EN_HOME.keys.length).toBeGreaterThan(150);
+    expect(ZH_HOME.keys.length).toBeGreaterThan(150);
+    expect(EN_KEYS.keys.length).toBe(new Set(EN_KEYS.keys).size);
+    expect(ZH_KEYS.keys.length).toBe(new Set(ZH_KEYS.keys).size);
   });
 
   it('the extractor really sees the keys the derivation implies', () => {
     // The strongest non-vacuity available: two INDEPENDENT channels for the
     // same fact. `SITES` comes from walking BLOCK_CONFIG; these sets come from
     // parsing the source text. A parser that silently stopped matching (a
     // reformat, a changed indent) fails here by name, not by going quiet.
-    const enSet = new Set(EN_TABLE.keys);
-    const zhSet = new Set(ZH_TABLE.keys);
+    const enSet = new Set(EN_KEYS.keys);
+    const zhSet = new Set(ZH_KEYS.keys);
     expect([...DERIVED].filter((k) => !enSet.has(k))).toEqual([]);
     expect([...DERIVED].filter((k) => !zhSet.has(k))).toEqual([]);
     expect(DERIVED.size).toBeGreaterThan(150);
@@ -693,8 +725,8 @@ describe('a retired key leaves BOTH locale tables (objectui#8368)', () => {
     // name and the fix is to teach the reader set about it, not to delete the
     // key. Loud is the correct direction to be wrong in.
     expect(
-      unreachable(EN_TABLE),
-      'ENGINE_STRINGS_EN keys under this prefix that BLOCK_CONFIG no longer implies and no ' +
+      unreachable(EN_KEYS),
+      'en keys under this prefix that BLOCK_CONFIG no longer implies and no ' +
         'shipped source asks for — delete them, or teach the reader set about the new reader',
     ).toEqual([]);
   });
@@ -704,19 +736,19 @@ describe('a retired key leaves BOTH locale tables (objectui#8368)', () => {
     // sibling `every key resolves in zh-CN` cannot see it — a LEFTOVER key
     // resolves perfectly well.
     expect(
-      unreachable(ZH_TABLE),
-      'ENGINE_STRINGS_ZH keys under this prefix that BLOCK_CONFIG no longer implies and no ' +
+      unreachable(ZH_KEYS),
+      'zh keys under this prefix that BLOCK_CONFIG no longer implies and no ' +
         'shipped source asks for — the half a rename forgets',
     ).toEqual([]);
   });
 
   it('both tables hold the same pageBlock key set', () => {
     // "Left BOTH tables", stated directly. Asymmetry here is the signature of a
     // half-applied retirement, and the message names which side kept the key.
-    const en = new Set(pageBlockKeys(EN_TABLE));
-    const zh = new Set(pageBlockKeys(ZH_TABLE));
-    expect([...en].filter((k) => !zh.has(k)), 'in ENGINE_STRINGS_EN but not ZH').toEqual([]);
-    expect([...zh].filter((k) => !en.has(k)), 'in ENGINE_STRINGS_ZH but not EN').toEqual([]);
+    const en = new Set(pageBlockKeys(EN_KEYS));
+    const zh = new Set(pageBlockKeys(ZH_KEYS));
+    expect([...en].filter((k) => !zh.has(k)), 'in the en homes but not zh').toEqual([]);
+    expect([...zh].filter((k) => !en.has(k)), 'in the zh homes but not en').toEqual([]);
     expect(en.size).toBeGreaterThan(150);
   });
 });