refactor(client): replace the per-field settings preference controller with a namespace settings scope

bindSettingsScope mirrors the Host-side settings owner seam in the browser:
one scope per namespace publishes a snapshot store (status, section value,
revision, writability, host/memory mode), validates sections against the
namespace's serialized wire schema via dsh-client-schema-form, and keeps the
controller's listener-before-read, revisioned serialized writes, latest-wins
publication, conflict recovery, and disposal quiescence. Theme, locale, and
busy-Enter services now take the scope as a constructor collaborator, which
removes the bindPersistence/syncPreference two-phase callback pair and the
defaulted no-op persist writers; hand-written wire guards fall away in favor
of the registered schema. test-runtime gains a stubSettingsScope double.

packages/client/ui-conversation/tests/host.spec.ts

@@ -4,7 +4,6 @@ import { Settings, settingsNamespace, type SettingsNamespace } from '@deepseek-a
 import {
   CONVERSATION_SETTINGS_NAMESPACE, DEFAULT_BUSY_ENTER_BEHAVIOR, apply,
 } from '@deepseek-ai/dsh-client-ui-conversation'
-import { isBusyEnterBehavior } from '../src/submission-settings.ts'
 
 class MemorySettings extends Settings {
   readonly writable = true
@@ -15,12 +14,6 @@ class MemorySettings extends Settings {
 }
 
 describe('ui-conversation host', () => {
-  it('narrows settings-wire values to the supported behavior pair', () => {
-    expect(isBusyEnterBehavior('queue')).toBe(true)
-    expect(isBusyEnterBehavior('steer')).toBe(true)
-    expect(isBusyEnterBehavior('later')).toBe(false)
-  })
-
   it('registers, validates, and disposes the durable busy-Enter preference', async () => {
     const ctx = new Context()
     await ctx.plugin(MemorySettings).await()

packages/client/ui-conversation/tests/submission-policy.spec.ts

@@ -1,8 +1,10 @@
 // @vitest-environment jsdom
 import { describe, expect, it, vi } from 'vitest'
+import { stubSettingsScope } from '@deepseek-ai/dsh-client-test-runtime'
 import {
   ComposerSubmissionPolicy, DEFAULT_BUSY_ENTER_BEHAVIOR,
 } from '../src/client/input/submission-policy.ts'
+import type { ConversationSettings } from '../src/submission-settings.ts'
 
 describe('ComposerSubmissionPolicy', () => {
   it('defaults to Queue and only applies the preference while running', () => {
@@ -16,8 +18,6 @@ describe('ComposerSubmissionPolicy', () => {
     expect(policy.resolve(true, 'accelerated', false)).toBe('queue')
 
     const changed = vi.fn()
-    const persist = vi.fn()
-    policy.bindPersistence(persist)
     policy.busyEnter.subscribe(changed)
     policy.setBusyEnter('steer')
     expect(changed).toHaveBeenCalledTimes(1)
@@ -25,25 +25,42 @@ describe('ComposerSubmissionPolicy', () => {
     expect(policy.resolve(true, 'accelerated', true)).toBe('queue')
     expect(policy.resolve(false, 'enter', true)).toBe('queue')
     expect(policy.resolve(false, 'accelerated', true)).toBe('queue')
-    expect(persist).toHaveBeenCalledWith('steer')
   })
 
-  it('syncs a Host preference without writing it back and leaves an identical write untouched', () => {
-    const persist = vi.fn()
-    const policy = new ComposerSubmissionPolicy(persist)
-    policy.syncPreference('steer')
+  it('writes an explicit change through the scope after publishing it locally', () => {
+    const host = stubSettingsScope<ConversationSettings>()
+    const observed: string[] = []
+    let liveBehavior = (): string => 'unconstructed'
+    const scope: typeof host.scope = {
+      ...host.scope,
+      set: (field, value) => {
+        observed.push(`${field}=${String(value)}:${liveBehavior()}`)
+        return host.scope.set(field, value)
+      },
+    }
+    const policy = new ComposerSubmissionPolicy(scope)
+    liveBehavior = () => policy.busyEnter.getSnapshot()
+    policy.setBusyEnter('steer')
+    expect(observed).toEqual(['busyEnter=steer:steer'])
+    expect(host.set).toHaveBeenCalledWith('busyEnter', 'steer')
+    expect(host.set).toHaveBeenCalledOnce()
+  })
+
+  it('adopts a Host preference without writing it back and leaves an identical write untouched', () => {
+    const host = stubSettingsScope<ConversationSettings>()
+    const policy = new ComposerSubmissionPolicy(host.scope)
+    host.publish({ status: 'ready', value: { busyEnter: 'steer' }, revision: 1, writable: true })
     expect(policy.busyEnter.getSnapshot()).toBe('steer')
     policy.setBusyEnter('steer')
-    expect(persist).not.toHaveBeenCalled()
+    expect(host.set).not.toHaveBeenCalled()
+    host.publish({ value: { busyEnter: 'steer' }, revision: 2 })
+    expect(policy.busyEnter.getSnapshot()).toBe('steer')
   })
 
-  it('publishes the in-memory preference before calling the durable writer', () => {
-    const policy = new ComposerSubmissionPolicy()
-    const persist = vi.fn(() => {
-      expect(policy.busyEnter.getSnapshot()).toBe('steer')
-    })
-    policy.bindPersistence(persist)
-    policy.setBusyEnter('steer')
-    expect(persist).toHaveBeenCalledOnce()
+  it('adopts a section already standing at construction', () => {
+    const host = stubSettingsScope<ConversationSettings>()
+    host.publish({ status: 'ready', value: { busyEnter: 'steer' }, revision: 1, writable: true })
+    const policy = new ComposerSubmissionPolicy(host.scope)
+    expect(policy.busyEnter.getSnapshot()).toBe('steer')
   })
 })