feat(client): typed locale standard seat in the slot framework

Registrations declare a dictionary namespace (locale: NS) and the renderer
synthesizes a typed t prop for the entry's component from the installed
LocaleFace; the seat binding is re-derived per locale revision, so a language
switch hands out fresh t references and memoized consumers re-render through
ordinary shallow comparison. LocaleNamespaceMap is the declare-merge table
(namespace -> dictionary key union); TranslateNS<'ns'> is the
namespace-addressed translate type (namespace keys plus the shared common
vocabulary), carried by the t seat and by the locale service's typed bind.

LocaleService implements the face (lookup ns -> common -> zh -> key,
revision-carrying snapshots with subscriber isolation) and installs it
through the boot-once slots.installLocale seam, mirroring the renderer
install. The typed register(ns, {zh, en}) overload checks each dictionary
against the namespace's key union and requires every shipped locale, so a
missing or extra key and an unbalanced translation are compile errors.
Dictionary registration bumps the face revision without emitting
locale/change — the event now means exactly 'the active locale switched',
so registration-heavy boot cannot storm event listeners.

packages/client/ui-model/tests/model-select.spec.tsx

@@ -3,8 +3,19 @@ import { cleanup, fireEvent, render, screen, waitFor } from '@testing-library/re
 import { afterEach, describe, expect, it, vi } from 'vitest'
 import type { ModelTarget } from '@deepseek-ai/dsh-client-connection/client'
 import { createSnapshotStore } from '@deepseek-ai/dsh-client-runtime/client'
+import type { ComponentProps } from 'react'
 import type { ModelDirectoryState } from '../src/client/directory.ts'
 import { ModelSelect } from '../src/client/ModelSelect.tsx'
+import { zh } from '../src/client/locales.ts'
+
+// The seat's key domain is model ∪ common; the stub answers from the package
+// dictionary (with template params) and falls back to the key like the real chain.
+const t: ComponentProps<typeof ModelSelect>['t'] = (key, params) => {
+  const template = (zh as Record<string, string>)[key] ?? key
+  return params === undefined
+    ? template
+    : template.replace(/\{(\w+)\}/g, (match, name: string) => name in params ? String(params[name]) : match)
+}
 
 const reasoning = {
   efforts: [
@@ -44,13 +55,14 @@ describe('ModelSelect reasoning effort', () => {
       directory={directory}
       load={vi.fn()}
       select={select}
+      t={t}
     />)
 
     const trigger = screen.getByRole('button', {
       name: '选择模型，当前 DeepSeek-V4-Flash，推理等级 High',
     })
     fireEvent.click(trigger)
-    fireEvent.click(screen.getByRole('menuitem', { name: /Effort/ }))
+    fireEvent.click(screen.getByRole('menuitem', { name: /推理等级/ }))
     expect(screen.getAllByRole('menuitemradio').map(item => item.textContent))
       .toEqual(['Off', 'High', 'MaxLargest budget'])
 
@@ -83,13 +95,14 @@ describe('ModelSelect reasoning effort', () => {
       directory={directory}
       load={vi.fn()}
       select={vi.fn().mockResolvedValue(true)}
+      t={t}
     />)
 
     fireEvent.click(screen.getByRole('button', {
-      name: '选择模型，当前 Model，推理等级 Provider default',
+      name: '选择模型，当前 Model，推理等级 服务商默认',
     }))
-    fireEvent.click(screen.getByRole('menuitem', { name: /Effort/ }))
+    fireEvent.click(screen.getByRole('menuitem', { name: /推理等级/ }))
     expect(screen.getAllByRole('menuitemradio').map(item => item.textContent))
-      .toEqual(['Provider default', 'Standard'])
+      .toEqual(['服务商默认', 'Standard'])
   })
 })