test(gui): apply-level suites for the feature-owned settings rows

Locale and ui-theme apply coverage on a real Context + SlotCore:
dictionary assembly, declaration-aware registration both ways,
inject-time getter re-sync, service write-back through the event flow,
HMR collapse recovery, and teardown reclamation. Four settings-surface
packages sit at full per-file coverage.

packages/client/ui-theme/tests/apply.spec.ts

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+/** ui-theme apply wiring: service provision, settings dictionaries riding the
+ * locale service, declaration-aware Appearance row registration, snapshot
+ * projection into the row store, and HMR collapse 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, SETTINGS_NS } from '@deepseek-ai/dsh-client-ui-theme/client'
+import type { AppearanceRowInjected, ThemeService } from '@deepseek-ai/dsh-client-ui-theme/client'
+import { AppearanceRow } from '../src/client/AppearanceRow.tsx'
+import type { createAppearanceRowStore } from '../src/client/settings-store.ts'
+
+const SLOT = 'settings.general.item'
+
+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 }
+}
+
+/** Stand in for the settings shell: declare the General item slot from root. */
+function declareItems(slots: SlotsService): () => void {
+  return slots.register(
+    { name: 'root', children: { [SLOT]: { 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(SLOT).find(e => e.component === AppearanceRow)!
+  const handle = entry.store as ReturnType<typeof createAppearanceRowStore>
+  const instance = handle.create()
+  const face = (entry.inject as unknown as (a: typeof instance.actions) => AppearanceRowInjected)(instance.actions)
+  return { entry, instance, face }
+}
+
+describe('ui-theme apply', () => {
+  it('declares the slot and locale services', () => {
+    expect(inject).toEqual(['slots', 'locale'])
+  })
+
+  it('provides the service, registers localized copy, and registers the row (declaration before or after apply)', async () => {
+    const before = await bench()
+    declareItems(before.slots)
+    await before.ctx.plugin({ inject: [...inject], apply }).await()
+    expect(before.locale.bind(SETTINGS_NS)('appearance.title')).toBe('外观')
+    before.locale.setLocale('en')
+    expect(before.locale.bind(SETTINGS_NS)('appearance.title')).toBe('Appearance')
+    const entry = before.slots.entries(SLOT).find(e => e.component === AppearanceRow)!
+    expect(entry.options).toMatchObject({ id: 'appearance', order: 10 })
+
+    const after = await bench()
+    const fiber = after.ctx.plugin({ inject: [...inject], apply })
+    await fiber.await()
+    expect(after.slots.entries(SLOT)).toHaveLength(0)
+    declareItems(after.slots)
+    await Promise.resolve()
+    expect(after.slots.entries(SLOT).some(e => e.component === AppearanceRow)).toBe(true)
+  })
+
+  it('projects service snapshots into the row store and routes face writes back', async () => {
+    const b = await bench()
+    declareItems(b.slots)
+    await b.ctx.plugin({ inject: [...inject], apply }).await()
+    const theme = b.ctx.get('theme') as ThemeService
+    // An event ahead of any inject hits the unbound-actions arm.
+    theme.setTheme('dark')
+
+    const { instance, face } = faceOf(b.slots)
+    // The inject-time re-sync sealed the init window: the mirror is current.
+    expect(instance.getSnapshot().preference).toBe('dark')
+    expect(face.t('appearance.dark')).toBe('深色')
+
+    face.setTheme('system')
+    expect(theme.getTheme().preference).toBe('system')
+    expect(instance.getSnapshot().preference).toBe('system')
+  })
+
+  it('recovers after an HMR collapse of the declaring entry (stale disposer must not block)', async () => {
+    const b = await bench()
+    const host = declareItems(b.slots)
+    await b.ctx.plugin({ inject: [...inject], apply }).await()
+    expect(b.slots.entries(SLOT)).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(SLOT)).toHaveLength(0)
+
+    declareItems(b.slots)
+    await Promise.resolve()
+    expect(b.slots.entries(SLOT).some(e => e.component === AppearanceRow)).toBe(true)
+  })
+
+  it('teardown removes the row and the dictionaries; teardown without a declaration is quiet', async () => {
+    const b = await bench()
+    declareItems(b.slots)
+    const fiber = b.ctx.plugin({ inject: [...inject], apply })
+    await fiber.await()
+    expect(b.slots.entries(SLOT)).toHaveLength(1)
+    await fiber.dispose()
+    expect(b.slots.entries(SLOT)).toHaveLength(0)
+    // Dictionary disposal: translation falls back to the bare key.
+    expect(b.locale.bind(SETTINGS_NS)('appearance.title')).toBe('appearance.title')
+
+    // Never-declared bench: the effect disposer's dispose arm stays undefined.
+    const quiet = await bench()
+    const f2 = quiet.ctx.plugin({ inject: [...inject], apply })
+    await f2.await()
+    await f2.dispose()
+    expect(quiet.slots.entries(SLOT)).toHaveLength(0)
+  })
+})