diff --git a/packages/client/ui-settings-general/src/client/index.ts b/packages/client/ui-settings-general/src/client/index.ts
index f8f8a73304..52655be7fa 100644
--- a/packages/client/ui-settings-general/src/client/index.ts
+++ b/packages/client/ui-settings-general/src/client/index.ts
@@ -98,9 +98,11 @@ export function apply(ctx: ClientContext): void {
     }
     // Nav labels are registrant-localized: re-register on locale change so
     // the ledger carries fresh text (the version bump re-renders the shell).
+    // The ledger check mirrors tryRegister: after an HMR collapse `dispose`
+    // stays set while the entry is gone — relabeling then must stay quiet.
     const offLocale = ctx.on('locale/change', () => {
-      if (!registered()) return
-      dispose?.()
+      if (dispose === undefined || !registered()) return
+      dispose()
       dispose = undefined
       tryRegister()
     })
diff --git a/packages/client/ui-settings-general/tests/apply.spec.ts b/packages/client/ui-settings-general/tests/apply.spec.ts
new file mode 100644
index 0000000000..8654275831
--- /dev/null
+++ b/packages/client/ui-settings-general/tests/apply.spec.ts
@@ -0,0 +1,139 @@
+/** apply wiring: dictionary registration, declaration-aware section entry,
+ * snapshot projection into the slot store, locale-driven relabeling, and
+ * recovery after an HMR collapse of the declaring entry. */
+import { Context } from 'cordis'
+import { describe, expect, it } from 'vitest'
+import { SlotsService } from '@deepseek-ai/dsh-client-runtime/client'
+import { LocaleService } from '@deepseek-ai/dsh-client-locale/client'
+import { ThemeService } from '@deepseek-ai/dsh-client-ui-theme/client'
+import { apply, inject } from '@deepseek-ai/dsh-client-ui-settings-general/client'
+import type { GeneralSectionInjected } from '@deepseek-ai/dsh-client-ui-settings-general/client'
+import { GeneralSection } from '../src/client/GeneralSection.tsx'
+import type { createGeneralSettingsStore } from '../src/client/store.ts'
+
+const NS = 'settings.general'
+
+async function bench() {
+  const ctx = new Context()
+  await ctx.plugin(SlotsService).await()
+  const locale = new LocaleService(ctx)
+  const theme = new ThemeService(ctx)
+  ctx.provide('locale', locale)
+  ctx.provide('theme', theme)
+  return { ctx, slots: ctx.get('slots') as SlotsService, locale, theme }
+}
+
+/** Stand in for the settings shell: declare the section list slot from root. */
+function declareSection(slots: SlotsService): () => void {
+  return slots.register(
+    { name: 'root', children: { 'settings.section': { kind: 'list', scope: 'root' } } } as never,
+    () => null,
+  )
+}
+
+/** Mirror the framework's inject choreography: bake a real instance from the
+ * declared handle and hand its actions to the entry's inject factory. */
+function faceOf(slots: SlotsService) {
+  const entry = slots.entries('settings.section')[0]!
+  const handle = entry.store as ReturnType<typeof createGeneralSettingsStore>
+  const instance = handle.create()
+  const face = (entry.inject as unknown as (a: typeof instance.actions) => GeneralSectionInjected)(instance.actions)
+  return { entry, instance, face }
+}
+
+describe('ui-settings-general apply', () => {
+  it('declares the slot, locale, and theme services', () => {
+    expect(inject).toEqual(['slots', 'locale', 'theme'])
+  })
+
+  it('registers dictionaries and the section entry for declarations before or after apply', async () => {
+    const before = await bench()
+    declareSection(before.slots)
+    await before.ctx.plugin({ inject: [...inject], apply }).await()
+    const entry = before.slots.entries('settings.section')[0]!
+    expect(entry.component).toBe(GeneralSection)
+    expect(entry.options).toMatchObject({ id: 'general', order: 0, label: '通用设置' })
+    expect(before.locale.bind(NS)('nav')).toBe('通用设置')
+
+    const after = await bench()
+    const fiber = after.ctx.plugin({ inject: [...inject], apply })
+    await fiber.await()
+    expect(after.slots.entries('settings.section')).toHaveLength(0)
+    declareSection(after.slots)
+    await Promise.resolve()
+    expect(after.slots.entries('settings.section')[0]!.component).toBe(GeneralSection)
+    // Teardown without a live registration exercises the undefined-disposer arm.
+    await fiber.dispose()
+    expect(after.slots.entries('settings.section')).toHaveLength(0)
+  })
+
+  it('projects service snapshots into the store and routes face writes back', async () => {
+    const b = await bench()
+    declareSection(b.slots)
+    await b.ctx.plugin({ inject: [...inject], apply }).await()
+    // Events ahead of any inject hit the unbound-actions arm without a store.
+    b.theme.setTheme('dark')
+
+    const { instance, face } = faceOf(b.slots)
+    // The inject-time re-sync sealed the init window: both mirrors are current.
+    expect(instance.getSnapshot().localeActive).toBe('zh')
+    expect(instance.getSnapshot().localeOptions.map(l => l.id)).toEqual(['zh', 'en'])
+    expect(instance.getSnapshot().themePreference).toBe('dark')
+    expect(face.t('nav')).toBe('通用设置')
+
+    face.setLocale('en')
+    expect(b.locale.getLocale().active).toBe('en')
+    expect(instance.getSnapshot().localeActive).toBe('en')
+    expect(face.t('nav')).toBe('General')
+
+    face.setTheme('system')
+    expect(b.theme.getTheme().preference).toBe('system')
+    expect(instance.getSnapshot().themePreference).toBe('system')
+  })
+
+  it('re-registers with a fresh ledger label when the locale changes', async () => {
+    const b = await bench()
+    declareSection(b.slots)
+    await b.ctx.plugin({ inject: [...inject], apply }).await()
+    expect(b.slots.entries('settings.section')[0]!.options.label).toBe('通用设置')
+    b.locale.setLocale('en')
+    const entry = b.slots.entries('settings.section')[0]!
+    expect(entry.options.label).toBe('General')
+    expect(entry.component).toBe(GeneralSection)
+  })
+
+  it('recovers after an HMR collapse of the declaring entry (stale disposer must not block)', async () => {
+    const b = await bench()
+    const host = declareSection(b.slots)
+    await b.ctx.plugin({ inject: [...inject], apply }).await()
+    expect(b.slots.entries('settings.section')).toHaveLength(1)
+
+    // Collapse: the declarer dies, the cascade removes our entry while the
+    // apply closure still holds its (now stale) disposer.
+    host()
+    expect(b.slots.entries('settings.section')).toHaveLength(0)
+
+    // A locale change inside the collapsed window must stay quiet.
+    b.locale.setLocale('en')
+    expect(b.slots.entries('settings.section')).toHaveLength(0)
+
+    // Redeclaration restores the entry — with the current locale's label.
+    declareSection(b.slots)
+    await Promise.resolve()
+    const entry = b.slots.entries('settings.section')[0]!
+    expect(entry.component).toBe(GeneralSection)
+    expect(entry.options.label).toBe('General')
+  })
+
+  it('removes the entry and the dictionaries on teardown', async () => {
+    const b = await bench()
+    declareSection(b.slots)
+    const fiber = b.ctx.plugin({ inject: [...inject], apply })
+    await fiber.await()
+    expect(b.slots.entries('settings.section')).toHaveLength(1)
+    await fiber.dispose()
+    expect(b.slots.entries('settings.section')).toHaveLength(0)
+    // Dictionary disposal: translation falls back to the bare key.
+    expect(b.locale.bind(NS)('nav')).toBe('nav')
+  })
+})
diff --git a/packages/client/ui-settings-general/tests/general-section.spec.tsx b/packages/client/ui-settings-general/tests/general-section.spec.tsx
new file mode 100644
index 0000000000..e82ed0b1fc
--- /dev/null
+++ b/packages/client/ui-settings-general/tests/general-section.spec.tsx
@@ -0,0 +1,112 @@
+// @vitest-environment jsdom
+/** GeneralSection behavior: skeleton rows stay inert, Language menu drives
+ * setLocale, Appearance cubes follow the preference and drive setTheme. */
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import { act, cleanup, fireEvent, render, screen } from '@testing-library/react'
+import { createSnapshotStore, type SessionListState, type WorkspaceListState } from '@deepseek-ai/dsh-client-runtime/client'
+import { bindSnapshotSelector } from '@deepseek-ai/dsh-client-web-react'
+import { GeneralSection } from '../src/client/GeneralSection.tsx'
+import { createGeneralSettingsStore } from '../src/client/store.ts'
+import { en } from '../src/client/locales.ts'
+import type { GeneralSectionComponentProps } from '../src/client/contract.ts'
+
+afterEach(cleanup)
+
+const LOCALES = [{ id: 'zh', label: '中文' }, { id: 'en', label: 'English' }]
+
+/** Empty global standard-kit hooks (the section reads neither). */
+function emptySessions() {
+  const store = createSnapshotStore<SessionListState>(
+    { ids: [], byId: {}, current: undefined, intent: undefined, phase: 'ready' })
+  return bindSnapshotSelector(store)
+}
+function emptyWorkspaces() {
+  const store = createSnapshotStore<WorkspaceListState>({
+    items: [], intent: undefined, state: 'idle', phase: 'ready', error: null,
+    baselinesReady: true, recentWorkspaceId: undefined,
+  })
+  return bindSnapshotSelector(store)
+}
+
+function mount(init?: { active?: string; preference?: 'light' | 'dark' | 'system' }) {
+  // Real store instance — the sanctioned zero-machinery path for tests.
+  const store = createGeneralSettingsStore().create()
+  store.actions.syncLocale(init?.active ?? 'en', LOCALES, 0)
+  store.actions.syncTheme(init?.preference ?? 'system', 0)
+  const setLocale = vi.fn()
+  const setTheme = vi.fn()
+  const props: GeneralSectionComponentProps = {
+    useSessions: emptySessions(),
+    useWorkspaces: emptyWorkspaces(),
+    useStore: bindSnapshotSelector(store),
+    actions: store.actions,
+    t: (key: string) => en[key] ?? key,
+    setLocale,
+    setTheme,
+  }
+  render(<GeneralSection {...props} />)
+  return { store, setLocale, setTheme }
+}
+
+const pressed = (name: RegExp): string | null =>
+  screen.getByRole('button', { name }).getAttribute('aria-pressed')
+
+describe('GeneralSection', () => {
+  it('renders the four groups with skeleton rows inert', () => {
+    const b = mount()
+    // Permission: disabled selector showing the fixed value.
+    const permission = screen.getByRole('button', { name: /Read only/ }) as HTMLButtonElement
+    expect(permission.disabled).toBe(true)
+    fireEvent.click(permission)
+    // Tool Call: both mode cubes render as plain text, no buttons.
+    expect(screen.getByText('Schema mode')).toBeDefined()
+    expect(screen.getByText('Code mode')).toBeDefined()
+    expect(screen.queryByRole('button', { name: /Schema mode/ })).toBeNull()
+    expect(b.setLocale).not.toHaveBeenCalled()
+    expect(b.setTheme).not.toHaveBeenCalled()
+  })
+
+  it('opens the language menu, selects a locale, and closes', () => {
+    const b = mount({ active: 'en' })
+    const trigger = screen.getByRole('button', { name: /English/ })
+    expect(trigger.getAttribute('aria-expanded')).toBe('false')
+    fireEvent.click(trigger)
+    expect(trigger.getAttribute('aria-expanded')).toBe('true')
+    fireEvent.click(screen.getByRole('menuitem', { name: '中文' }))
+    expect(b.setLocale).toHaveBeenCalledWith('zh')
+    expect(trigger.getAttribute('aria-expanded')).toBe('false')
+    expect(screen.queryByRole('menuitem', { name: '中文' })).toBeNull()
+  })
+
+  it('closes the language menu on outside pointerdown without selecting', () => {
+    const b = mount({ active: 'en' })
+    const trigger = screen.getByRole('button', { name: /English/ })
+    fireEvent.click(trigger)
+    expect(screen.getByRole('menuitem', { name: '中文' })).toBeDefined()
+    fireEvent.pointerDown(document.body)
+    expect(trigger.getAttribute('aria-expanded')).toBe('false')
+    expect(screen.queryByRole('menuitem', { name: '中文' })).toBeNull()
+    expect(b.setLocale).not.toHaveBeenCalled()
+  })
+
+  it('reflects a store locale change in the trigger label (unknown id falls back to the id)', () => {
+    const b = mount({ active: 'en' })
+    act(() => { b.store.actions.syncLocale('zh', LOCALES, 1) })
+    expect(screen.getByRole('button', { name: /中文/ })).toBeDefined()
+    act(() => { b.store.actions.syncLocale('fr', LOCALES, 2) })
+    expect(screen.getByRole('button', { name: /fr/ })).toBeDefined()
+  })
+
+  it('marks the appearance cube matching the preference and switches on click', () => {
+    const b = mount({ preference: 'dark' })
+    expect(pressed(/Dark/)).toBe('true')
+    expect(pressed(/Light/)).toBe('false')
+    expect(pressed(/System/)).toBe('false')
+    fireEvent.click(screen.getByRole('button', { name: /Light/ }))
+    expect(b.setTheme).toHaveBeenCalledWith('light')
+    // Selection follows the store mirror, not the click echo.
+    act(() => { b.store.actions.syncTheme('light', 1) })
+    expect(pressed(/Light/)).toBe('true')
+    expect(pressed(/Dark/)).toBe('false')
+  })
+})
diff --git a/packages/client/ui-settings-general/tests/invariant.spec.ts b/packages/client/ui-settings-general/tests/invariant.spec.ts
new file mode 100644
index 0000000000..7b0527c0ff
--- /dev/null
+++ b/packages/client/ui-settings-general/tests/invariant.spec.ts
@@ -0,0 +1,18 @@
+import { describe, expect, it } from 'vitest'
+import { Context } from 'cordis'
+import * as GeneralInvariant from '@deepseek-ai/dsh-client-ui-settings-general/invariant'
+import InvariantService from '@deepseek-ai/dsh-invariants'
+
+describe('invariant companion', () => {
+  it('registers under the package name with an empty installer', async () => {
+    const ctx = new Context()
+    await ctx.plugin(InvariantService, { enabled: true })
+    await expect(ctx.plugin(GeneralInvariant).await()).resolves.toBeDefined()
+  })
+
+  it('node-half apply is a no-op host placeholder', async () => {
+    const { apply } = await import('@deepseek-ai/dsh-client-ui-settings-general')
+    apply()
+    expect(true).toBe(true) // reaching here without throw is the contract
+  })
+})
diff --git a/packages/client/ui-settings-general/tests/store.spec.ts b/packages/client/ui-settings-general/tests/store.spec.ts
new file mode 100644
index 0000000000..b291418471
--- /dev/null
+++ b/packages/client/ui-settings-general/tests/store.spec.ts
@@ -0,0 +1,56 @@
+/** General settings store: snapshot-mirror actions and the revision guard. */
+import { describe, expect, it } from 'vitest'
+import { createGeneralSettingsStore } from '../src/client/store.ts'
+
+const LOCALES = [{ id: 'zh', label: '中文' }, { id: 'en', label: 'English' }]
+
+describe('createGeneralSettingsStore', () => {
+  it('init shape: empty mirrors with revisions at -1', () => {
+    const store = createGeneralSettingsStore().create()
+    expect(store.getSnapshot()).toEqual({
+      localeActive: '',
+      localeOptions: [],
+      localeRevision: -1,
+      themePreference: 'system',
+      themeRevision: -1,
+    })
+  })
+
+  it('syncLocale mirrors the snapshot and advances the revision', () => {
+    const store = createGeneralSettingsStore().create()
+    store.actions.syncLocale('zh', LOCALES, 0)
+    expect(store.getSnapshot().localeActive).toBe('zh')
+    expect(store.getSnapshot().localeOptions).toEqual(LOCALES)
+    expect(store.getSnapshot().localeRevision).toBe(0)
+
+    store.actions.syncLocale('en', LOCALES, 1)
+    expect(store.getSnapshot().localeActive).toBe('en')
+    expect(store.getSnapshot().localeRevision).toBe(1)
+  })
+
+  it('syncLocale revision guard drops stale and duplicate writes', () => {
+    const store = createGeneralSettingsStore().create()
+    store.actions.syncLocale('en', LOCALES, 5)
+    // Stale (lower) and duplicate (equal) revisions leave the mirror intact.
+    store.actions.syncLocale('zh', LOCALES, 4)
+    store.actions.syncLocale('zh', LOCALES, 5)
+    expect(store.getSnapshot().localeActive).toBe('en')
+    expect(store.getSnapshot().localeRevision).toBe(5)
+  })
+
+  it('syncTheme mirrors the preference and guards its revision independently', () => {
+    const store = createGeneralSettingsStore().create()
+    store.actions.syncTheme('dark', 0)
+    expect(store.getSnapshot().themePreference).toBe('dark')
+    expect(store.getSnapshot().themeRevision).toBe(0)
+
+    store.actions.syncTheme('light', 2)
+    expect(store.getSnapshot().themePreference).toBe('light')
+
+    // Stale theme write is dropped; the locale revision axis is untouched.
+    store.actions.syncTheme('system', 1)
+    expect(store.getSnapshot().themePreference).toBe('light')
+    expect(store.getSnapshot().themeRevision).toBe(2)
+    expect(store.getSnapshot().localeRevision).toBe(-1)
+  })
+})
diff --git a/packages/client/ui-settings-models/src/client/index.ts b/packages/client/ui-settings-models/src/client/index.ts
index 8ad2ebb750..c35946fcc8 100644
--- a/packages/client/ui-settings-models/src/client/index.ts
+++ b/packages/client/ui-settings-models/src/client/index.ts
@@ -31,9 +31,15 @@ export function apply(ctx: ClientContext): void {
     ]
     return () => { for (const dispose of disposers) dispose() }
   }, 'ui-settings-models: nav copy dictionaries')
+  // Declaration-aware registration; the LEDGER is the has-registered judge
+  // (not a local flag): after an HMR collapse re-declares the slot, the
+  // cascade already removed our entry, and a stale disposer must not block
+  // the re-registration.
   ctx.effect(() => {
     let dispose: (() => void) | undefined
-    const register = (): void => {
+    const tryRegister = (): void => {
+      if (ctx.slots.spec('settings.section') === undefined) return
+      if (ctx.slots.entries('settings.section').some(e => e.component === ModelsSection)) return
       dispose = ctx.slots.register({
         name: 'settings.section',
         id: 'models',
@@ -41,16 +47,14 @@ export function apply(ctx: ClientContext): void {
         label: ctx.locale.bind('settings.models')('nav'),
       }, ModelsSection)
     }
-    const tryRegister = (): void => {
-      if (ctx.slots.spec('settings.section') === undefined || dispose !== undefined) return
-      register()
-    }
     // Nav labels are registrant-localized: re-register on locale change so
     // the ledger carries fresh text (the version bump re-renders the shell).
+    // Dispose-then-requery: after an HMR collapse the disposer is stale and
+    // the ledger/spec re-check keeps this path an idempotent no-op.
     const offLocale = ctx.on('locale/change', () => {
-      if (dispose === undefined) return
-      dispose()
-      register()
+      dispose?.()
+      dispose = undefined
+      tryRegister()
     })
     const unsubscribe = ctx.slots.subscribe('settings.section', () => { tryRegister() })
     tryRegister()
diff --git a/packages/client/ui-settings-models/tests/apply.spec.ts b/packages/client/ui-settings-models/tests/apply.spec.ts
new file mode 100644
index 0000000000..b7aa3cf2ab
--- /dev/null
+++ b/packages/client/ui-settings-models/tests/apply.spec.ts
@@ -0,0 +1,95 @@
+/** Models section registration: declaration-aware deferral, locale re-registration, and HMR recovery. */
+import { Context } from 'cordis'
+import { describe, expect, it } from 'vitest'
+import { SlotsService } from '@deepseek-ai/dsh-client-runtime/client'
+import { LocaleService } from '@deepseek-ai/dsh-client-locale/client'
+import { apply, inject } from '@deepseek-ai/dsh-client-ui-settings-models/client'
+import { ModelsSection } from '../src/client/ModelsSection.tsx'
+
+async function bench() {
+  const ctx = new Context()
+  await ctx.plugin(SlotsService).await()
+  const locale = new LocaleService(ctx)
+  ctx.provide('locale', locale)
+  return { ctx, slots: ctx.get('slots') as SlotsService, locale }
+}
+
+function declare(slots: SlotsService): () => void {
+  return slots.register(
+    { name: 'root', children: { 'settings.section': { kind: 'list', scope: 'root' } } } as never,
+    () => null,
+  )
+}
+
+describe('ui-settings-models apply', () => {
+  it('declares the services it uses', () => {
+    expect(inject).toEqual(['slots', 'locale'])
+  })
+
+  it('registers the models nav entry for declarations before or after apply', async () => {
+    const before = await bench()
+    declare(before.slots)
+    await before.ctx.plugin({ inject: [...inject], apply }).await()
+    const entry = before.slots.entries('settings.section')[0]!
+    expect(entry.component).toBe(ModelsSection)
+    expect(entry.options).toEqual({ id: 'models', order: 10, label: '模型' })
+
+    const after = await bench()
+    await after.ctx.plugin({ inject: [...inject], apply }).await()
+    expect(after.slots.entries('settings.section')).toHaveLength(0)
+    declare(after.slots)
+    await Promise.resolve()
+    expect(after.slots.entries('settings.section')[0]!.component).toBe(ModelsSection)
+    // The self-inflicted ledger notifications hit the duplicate guard.
+    expect(after.slots.entries('settings.section')).toHaveLength(1)
+  })
+
+  it('re-registers with fresh label text on locale change', async () => {
+    const b = await bench()
+    declare(b.slots)
+    await b.ctx.plugin({ inject: [...inject], apply }).await()
+    b.locale.setLocale('en')
+    expect(b.slots.entries('settings.section')[0]!.options.label).toBe('Models')
+    b.locale.setLocale('zh')
+    expect(b.slots.entries('settings.section')[0]!.options.label).toBe('模型')
+  })
+
+  it('locale change while the slot is undeclared stays a no-op', async () => {
+    const b = await bench()
+    await b.ctx.plugin({ inject: [...inject], apply }).await()
+    b.locale.setLocale('en')
+    expect(b.slots.entries('settings.section')).toHaveLength(0)
+    b.locale.setLocale('zh')
+  })
+
+  it('re-registers after an HMR collapse re-declares the slot (stale disposer must not block)', async () => {
+    const b = await bench()
+    const redeclare = declare(b.slots)
+    await b.ctx.plugin({ inject: [...inject], apply }).await()
+    expect(b.slots.entries('settings.section')).toHaveLength(1)
+    // Declarer unload: the cascade removes our entry while our local
+    // disposer variable goes stale.
+    redeclare()
+    expect(b.slots.entries('settings.section')).toHaveLength(0)
+    declare(b.slots)
+    await Promise.resolve()
+    expect(b.slots.entries('settings.section')[0]!.component).toBe(ModelsSection)
+    // The locale path also recovers through the same ledger re-check.
+    b.locale.setLocale('en')
+    expect(b.slots.entries('settings.section')[0]!.options.label).toBe('Models')
+    b.locale.setLocale('zh')
+  })
+
+  it('registers the zh/en nav dictionaries and disposes everything with the fiber', async () => {
+    const b = await bench()
+    declare(b.slots)
+    const fiber = b.ctx.plugin({ inject: [...inject], apply })
+    await fiber.await()
+    expect(b.locale.bind('settings.models')('nav')).toBe('模型')
+    await fiber.dispose()
+    expect(b.slots.entries('settings.section')).toHaveLength(0)
+    // The (ns, locale) seats are free again — the dictionary disposers ran.
+    expect(() => b.locale.register('settings.models', 'zh', {})).not.toThrow()
+    expect(() => b.locale.register('settings.models', 'en', {})).not.toThrow()
+  })
+})
diff --git a/packages/client/ui-settings-models/tests/invariant.spec.ts b/packages/client/ui-settings-models/tests/invariant.spec.ts
new file mode 100644
index 0000000000..65c7c1094a
--- /dev/null
+++ b/packages/client/ui-settings-models/tests/invariant.spec.ts
@@ -0,0 +1,23 @@
+import { describe, expect, it } from 'vitest'
+import { Context } from 'cordis'
+import * as ModelsInvariant from '@deepseek-ai/dsh-client-ui-settings-models/invariant'
+import InvariantService from '@deepseek-ai/dsh-invariants'
+import { ModelsSection } from '../src/client/ModelsSection.tsx'
+
+describe('invariant companion', () => {
+  it('registers under the package name with an empty installer', async () => {
+    const ctx = new Context()
+    await ctx.plugin(InvariantService, { enabled: true })
+    await expect(ctx.plugin(ModelsInvariant).await()).resolves.toBeDefined()
+  })
+
+  it('node-half apply is a no-op host placeholder', async () => {
+    const { apply } = await import('@deepseek-ai/dsh-client-ui-settings-models')
+    apply()
+    expect(true).toBe(true) // reaching here without throw is the contract
+  })
+
+  it('the section content column is intentionally empty this phase', () => {
+    expect(ModelsSection()).toBeNull()
+  })
+})
diff --git a/packages/client/ui-settings/src/client/index.ts b/packages/client/ui-settings/src/client/index.ts
index d5135f373c..688436c25b 100644
--- a/packages/client/ui-settings/src/client/index.ts
+++ b/packages/client/ui-settings/src/client/index.ts
@@ -43,13 +43,23 @@ export function apply(ctx: ClientContext): void {
     sectionsVersion: () => ctx.slots.getVersion('settings.section'),
     subscribeSections: (listener) => ctx.slots.subscribe('settings.section', listener),
     sections: () => ctx.slots.entries('settings.section')
-      .map(e => ({ id: e.options.id ?? '', order: e.options.order ?? 0, label: e.options.label ?? '' }))
+      .map(e => ({
+        /* v8 ignore next -- list-slot registration requires id (SlotCore rejects an entry without one) */
+        id: e.options.id ?? '',
+        order: e.options.order ?? 0,
+        label: e.options.label ?? '',
+      }))
       .sort((a, b) => a.order - b.order),
   })
+  // Declaration-aware registration; the LEDGER is the has-registered judge
+  // (not a local flag): after an HMR collapse re-declares the slot, the
+  // cascade already removed our entry, and a stale disposer must not block
+  // the re-registration.
   ctx.effect(() => {
     let dispose: (() => void) | undefined
     const tryRegister = (): void => {
-      if (ctx.slots.spec('sidebar.settings') === undefined || dispose !== undefined) return
+      if (ctx.slots.spec('sidebar.settings') === undefined) return
+      if (ctx.slots.entries('sidebar.settings').some(e => e.component === SettingsRoot)) return
       dispose = ctx.slots.register({
         name: 'sidebar.settings',
         children: { 'settings.section': { kind: 'list', scope: 'root' } },
diff --git a/packages/client/ui-settings/tests/apply.spec.ts b/packages/client/ui-settings/tests/apply.spec.ts
new file mode 100644
index 0000000000..a94406e4ce
--- /dev/null
+++ b/packages/client/ui-settings/tests/apply.spec.ts
@@ -0,0 +1,120 @@
+/** Settings shell registration: declaration-aware deferral, the injected face, and HMR recovery. */
+import { Context } from 'cordis'
+import { describe, expect, it, vi } from 'vitest'
+import { SlotsService } from '@deepseek-ai/dsh-client-runtime/client'
+import { LocaleService } from '@deepseek-ai/dsh-client-locale/client'
+import { apply, inject } from '@deepseek-ai/dsh-client-ui-settings/client'
+import type { SettingsRootInjected } from '@deepseek-ai/dsh-client-ui-settings/client'
+import { SettingsRoot } from '../src/client/SettingsRoot.tsx'
+
+async function bench() {
+  const ctx = new Context()
+  await ctx.plugin(SlotsService).await()
+  const locale = new LocaleService(ctx)
+  ctx.provide('locale', locale)
+  return { ctx, slots: ctx.get('slots') as SlotsService, locale }
+}
+
+function declare(slots: SlotsService): () => void {
+  return slots.register(
+    { name: 'root', children: { 'sidebar.settings': { kind: 'single', scope: 'root' } } } as never,
+    () => null,
+  )
+}
+
+function injectedOf(slots: SlotsService): SettingsRootInjected {
+  const entry = slots.entries('sidebar.settings')[0]!
+  return (entry.inject as () => SettingsRootInjected)()
+}
+
+describe('ui-settings apply', () => {
+  it('declares the services it uses', () => {
+    expect(inject).toEqual(['slots', 'locale'])
+  })
+
+  it('registers the shell for declarations that arrive before or after apply', async () => {
+    const before = await bench()
+    declare(before.slots)
+    await before.ctx.plugin({ inject: [...inject], apply }).await()
+    expect(before.slots.entries('sidebar.settings')[0]!.component).toBe(SettingsRoot)
+    expect(before.slots.spec('settings.section')).toEqual({ kind: 'list', scope: 'root' })
+
+    const after = await bench()
+    await after.ctx.plugin({ inject: [...inject], apply }).await()
+    expect(after.slots.entries('sidebar.settings')).toHaveLength(0)
+    declare(after.slots)
+    await Promise.resolve()
+    expect(after.slots.entries('sidebar.settings')[0]!.component).toBe(SettingsRoot)
+    // The self-inflicted ledger notifications hit the duplicate guard.
+    expect(after.slots.entries('sidebar.settings')).toHaveLength(1)
+  })
+
+  it('registers the zh/en shell dictionaries and disposes them with the fiber', async () => {
+    const b = await bench()
+    declare(b.slots)
+    const fiber = b.ctx.plugin({ inject: [...inject], apply })
+    await fiber.await()
+    expect(b.locale.bind('settings')('title')).toBe('设置')
+    b.locale.setLocale('en')
+    expect(b.locale.bind('settings')('close')).toBe('Close')
+    await fiber.dispose()
+    // The (ns, locale) seats are free again — the dictionary disposers ran.
+    expect(() => b.locale.register('settings', 'zh', {})).not.toThrow()
+    expect(() => b.locale.register('settings', 'en', {})).not.toThrow()
+  })
+
+  it('exposes translate over "<ns>:<key>" refs with literal echo for plain text', async () => {
+    const b = await bench()
+    declare(b.slots)
+    await b.ctx.plugin({ inject: [...inject], apply }).await()
+    const injected = injectedOf(b.slots)
+    expect(injected.translate('settings:title')).toBe('设置')
+    expect(injected.translate('no colon ref')).toBe('no colon ref')
+  })
+
+  it('projects the section ledger into ordered nav rows with option defaults', async () => {
+    const b = await bench()
+    declare(b.slots)
+    await b.ctx.plugin({ inject: [...inject], apply }).await()
+    const injected = injectedOf(b.slots)
+    expect(injected.sections()).toEqual([])
+    b.slots.register({ name: 'settings.section', id: 'z', order: 20, label: 'Z' } as never, () => null)
+    b.slots.register({ name: 'settings.section', id: 'a' } as never, () => null)
+    expect(injected.sections()).toEqual([
+      { id: 'a', order: 0, label: '' },
+      { id: 'z', order: 20, label: 'Z' },
+    ])
+    expect(injected.sectionsVersion()).toBe(b.slots.getVersion('settings.section'))
+    const listener = vi.fn()
+    const off = injected.subscribeSections(listener)
+    b.slots.register({ name: 'settings.section', id: 'b', order: 1, label: 'B' } as never, () => null)
+    await Promise.resolve()
+    expect(listener).toHaveBeenCalled()
+    off()
+  })
+
+  it('re-registers after an HMR collapse re-declares the slot (stale disposer must not block)', async () => {
+    const b = await bench()
+    const redeclare = declare(b.slots)
+    await b.ctx.plugin({ inject: [...inject], apply }).await()
+    expect(b.slots.entries('sidebar.settings')).toHaveLength(1)
+    // Declarer unload: the cascade removes our entry and the slot spec while
+    // our local disposer variable goes stale.
+    redeclare()
+    expect(b.slots.entries('sidebar.settings')).toHaveLength(0)
+    declare(b.slots)
+    await Promise.resolve()
+    expect(b.slots.entries('sidebar.settings')[0]!.component).toBe(SettingsRoot)
+    expect(b.slots.spec('settings.section')).toEqual({ kind: 'list', scope: 'root' })
+  })
+
+  it('unregisters the shell and collapses settings.section on teardown', async () => {
+    const b = await bench()
+    declare(b.slots)
+    const fiber = b.ctx.plugin({ inject: [...inject], apply })
+    await fiber.await()
+    await fiber.dispose()
+    expect(b.slots.entries('sidebar.settings')).toHaveLength(0)
+    expect(b.slots.spec('settings.section')).toBeUndefined()
+  })
+})
diff --git a/packages/client/ui-settings/tests/invariant.spec.ts b/packages/client/ui-settings/tests/invariant.spec.ts
new file mode 100644
index 0000000000..c3474d5bdd
--- /dev/null
+++ b/packages/client/ui-settings/tests/invariant.spec.ts
@@ -0,0 +1,18 @@
+import { describe, expect, it } from 'vitest'
+import { Context } from 'cordis'
+import * as SettingsInvariant from '@deepseek-ai/dsh-client-ui-settings/invariant'
+import InvariantService from '@deepseek-ai/dsh-invariants'
+
+describe('invariant companion', () => {
+  it('registers under the package name with an empty installer', async () => {
+    const ctx = new Context()
+    await ctx.plugin(InvariantService, { enabled: true })
+    await expect(ctx.plugin(SettingsInvariant).await()).resolves.toBeDefined()
+  })
+
+  it('node-half apply is a no-op host placeholder', async () => {
+    const { apply } = await import('@deepseek-ai/dsh-client-ui-settings')
+    apply()
+    expect(true).toBe(true) // reaching here without throw is the contract
+  })
+})
diff --git a/packages/client/ui-settings/tests/settings-root.spec.tsx b/packages/client/ui-settings/tests/settings-root.spec.tsx
new file mode 100644
index 0000000000..ab56365075
--- /dev/null
+++ b/packages/client/ui-settings/tests/settings-root.spec.tsx
@@ -0,0 +1,155 @@
+// @vitest-environment jsdom
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import { act, cleanup, fireEvent, render, screen } from '@testing-library/react'
+import type { SettingsRootComponentProps } from '../src/client/contract/slots.ts'
+import { SettingsRoot } from '../src/client/SettingsRoot.tsx'
+
+afterEach(cleanup)
+
+const DICT: Record<string, string> = {
+  'settings:trigger': 'Settings',
+  'settings:title': 'Settings',
+  'settings:close': 'Close',
+}
+
+type Row = { id: string; order: number; label: string }
+
+function mount({
+  wide = true,
+  rows = [
+    { id: 'general', order: 0, label: 'General' },
+    { id: 'models', order: 10, label: 'Models' },
+  ],
+}: { wide?: boolean; rows?: Row[] } = {}) {
+  // Mutable row store standing in for the ledger; bump() plays a change.
+  let current = rows
+  let version = 0
+  const listeners = new Set<() => void>()
+  const renderSlot = vi.fn(
+    ((_key: string, _owner: unknown, opts?: { only?: string }) =>
+      <div data-testid={`section-${opts?.only ?? 'all'}`} />) as SettingsRootComponentProps['renderSlot'],
+  )
+  // Global standard kit stubs: the shell consumes neither hook.
+  const unusedHook = (() => { throw new Error('unused by SettingsRoot') }) as never
+  const props: SettingsRootComponentProps = {
+    useSessions: unusedHook,
+    useWorkspaces: unusedHook,
+    wide,
+    translate: (ref) => DICT[ref] ?? ref,
+    sectionsVersion: () => version,
+    subscribeSections: (listener) => {
+      listeners.add(listener)
+      return () => { listeners.delete(listener) }
+    },
+    sections: () => current,
+    renderSlot,
+  }
+  const view = render(<SettingsRoot {...props} />)
+  const bump = (next: Row[]) => {
+    act(() => {
+      current = next
+      version += 1
+      for (const fn of [...listeners]) fn()
+    })
+  }
+  return { view, renderSlot, bump, listeners }
+}
+
+function openPanel() {
+  fireEvent.click(screen.getByRole('button', { name: 'Settings' }))
+}
+
+describe('SettingsRoot trigger', () => {
+  it('renders the wide row with the label and opens the dialog', () => {
+    mount()
+    const trigger = screen.getByRole('button', { name: 'Settings' })
+    expect(trigger.textContent).toContain('Settings')
+    expect(trigger.getAttribute('aria-expanded')).toBe('false')
+    fireEvent.click(trigger)
+    expect(screen.getByRole('dialog')).toBeTruthy()
+    expect(screen.getByRole('button', { name: 'Settings', expanded: true })).toBeTruthy()
+  })
+
+  it('drops the label in the rail state', () => {
+    mount({ wide: false })
+    expect(screen.getByRole('button', { name: 'Settings' }).textContent).toBe('')
+  })
+})
+
+describe('SettingsPanel close paths', () => {
+  it('closes via the header button', () => {
+    mount()
+    openPanel()
+    fireEvent.click(screen.getByRole('button', { name: 'Close' }))
+    expect(screen.queryByRole('dialog')).toBeNull()
+  })
+
+  it('closes via a mask click', () => {
+    mount()
+    openPanel()
+    const dialog = screen.getByRole('dialog')
+    fireEvent.click(dialog.parentElement!.firstElementChild!)
+    expect(screen.queryByRole('dialog')).toBeNull()
+  })
+
+  it('closes via document-level Escape and unhooks the listener with the panel', () => {
+    mount()
+    openPanel()
+    fireEvent.keyDown(document, { key: 'Escape' })
+    expect(screen.queryByRole('dialog')).toBeNull()
+    // Ignored while closed (listener removed with the panel) and non-Escape
+    // keys are ignored while open.
+    fireEvent.keyDown(document, { key: 'Escape' })
+    openPanel()
+    fireEvent.keyDown(document, { key: 'Enter' })
+    expect(screen.getByRole('dialog')).toBeTruthy()
+  })
+
+  it('lands focus on the close button when the dialog opens', () => {
+    mount()
+    openPanel()
+    expect(document.activeElement).toBe(screen.getByRole('button', { name: 'Close' }))
+  })
+})
+
+describe('SettingsPanel navigation', () => {
+  it('projects rows, marks the first active, and renders only that section', () => {
+    mount()
+    openPanel()
+    expect(screen.getByRole('button', { name: 'General' }).getAttribute('aria-current')).toBe('true')
+    expect(screen.getByRole('button', { name: 'Models' }).getAttribute('aria-current')).toBeNull()
+    expect(screen.getByTestId('section-general')).toBeTruthy()
+  })
+
+  it('switches the rendered section on nav click', () => {
+    mount()
+    openPanel()
+    fireEvent.click(screen.getByRole('button', { name: 'Models' }))
+    expect(screen.getByRole('button', { name: 'Models' }).getAttribute('aria-current')).toBe('true')
+    expect(screen.getByTestId('section-models')).toBeTruthy()
+    expect(screen.queryByTestId('section-general')).toBeNull()
+  })
+
+  it('falls back to the first row when the active entry unregisters', () => {
+    const { bump } = mount()
+    openPanel()
+    fireEvent.click(screen.getByRole('button', { name: 'Models' }))
+    bump([{ id: 'general', order: 0, label: 'General' }])
+    expect(screen.queryByRole('button', { name: 'Models' })).toBeNull()
+    expect(screen.getByTestId('section-general')).toBeTruthy()
+  })
+
+  it('renders an empty content column when the ledger is empty', () => {
+    const { renderSlot } = mount({ rows: [] })
+    openPanel()
+    expect(screen.getByRole('dialog')).toBeTruthy()
+    expect(renderSlot).not.toHaveBeenCalled()
+  })
+
+  it('drops the ledger subscription on unmount', () => {
+    const { view, listeners } = mount()
+    expect(listeners.size).toBe(1)
+    view.unmount()
+    expect(listeners.size).toBe(0)
+  })
+})