refactor(client): name the compile face in every client test filename

A test file under packages/client now says which face it covers:
`*.client.spec.{ts,tsx}` and its `*.client.{ts,tsx}` helpers belong to the
Client aggregate, `*.host.spec.ts` to the host aggregate. The carrier's four
node-half specs take the Host suffix.

The two suffixes are mutually exclusive, so each aggregate excludes the
other's and both keep one broad test glob: `exclude` wins over `include`, and
`packages/client/**` no longer has to be excluded wholesale from the host
program with per-file `files` entries carved back out of it. A Host-face spec
that reaches only Host source therefore needs no cross-face project
reference, which the split-project rule rejects.

vitest still discovers every file through `**/*.spec.{ts,tsx}`.

packages/client/ui-layout/tests/service.client.spec.ts

@@ -0,0 +1,58 @@
+/**
+ * LayoutService behavior: the cross-plugin panel-action face. Geometry
+ * lives in the entry store (layout-store.spec.ts) — here we assert the
+ * delegation contract: attachPanels wiring, the three actions forwarding, the
+ * unwired fail-loud, and re-attach overwriting a stale action set.
+ */
+import { describe, expect, it, vi } from 'vitest'
+import { LayoutService } from '@deepseek-ai/dsh-client-ui-layout/src/client/service.ts'
+import type { PanelActions } from '@deepseek-ai/dsh-client-ui-layout/src/client/service.ts'
+
+function fakePanels(): PanelActions {
+  return {
+    setSidebar: vi.fn(),
+    setDetails: vi.fn(),
+    toggleSidebar: vi.fn(),
+    setNarrow: vi.fn(),
+    openDetails: vi.fn(),
+    closeDetails: vi.fn(),
+  }
+}
+
+describe('LayoutService', () => {
+  it('forwards the three panel actions to the attached set', () => {
+    const service = new LayoutService()
+    const panels = fakePanels()
+    service.attachPanels(panels)
+
+    service.toggleSidebar()
+    service.openDetails()
+    service.closeDetails()
+
+    expect(panels.toggleSidebar).toHaveBeenCalledTimes(1)
+    expect(panels.openDetails).toHaveBeenCalledTimes(1)
+    expect(panels.closeDetails).toHaveBeenCalledTimes(1)
+    expect(panels.setSidebar).not.toHaveBeenCalled()
+    expect(panels.setDetails).not.toHaveBeenCalled()
+  })
+
+  it('fails loud before the root entry wired its actions', () => {
+    const service = new LayoutService()
+    expect(() => { service.toggleSidebar() }).toThrow(/panel actions not wired/)
+    expect(() => { service.openDetails() }).toThrow(/panel actions not wired/)
+    expect(() => { service.closeDetails() }).toThrow(/panel actions not wired/)
+  })
+
+  it('re-attach overwrites the stale action set (entry re-register)', () => {
+    const service = new LayoutService()
+    const stale = fakePanels()
+    const fresh = fakePanels()
+    service.attachPanels(stale)
+    service.attachPanels(fresh)
+
+    service.toggleSidebar()
+
+    expect(stale.toggleSidebar).not.toHaveBeenCalled()
+    expect(fresh.toggleSidebar).toHaveBeenCalledTimes(1)
+  })
+})