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-settings-general/tests/settings-document-store.client.spec.ts

@@ -0,0 +1,132 @@
+import { describe, expect, it, vi } from 'vitest'
+import type { RpcResponse } from '@deepseek-ai/dsh-api-remotes/client'
+import { SettingsDocumentStore } from '../src/client/settings-document-store.ts'
+
+function response(hasDocument = false): RpcResponse<{
+  writable: boolean
+  hasDocument: boolean
+  namespaces: []
+}> {
+  return {
+    rpcId: 'settings-document' as never,
+    result: {
+      ok: true,
+      value: { writable: true, hasDocument, namespaces: [] },
+    },
+  }
+}
+
+function opened(): RpcResponse<{ opened: true }> {
+  return {
+    rpcId: 'settings-open' as never,
+    result: { ok: true, value: { opened: true } },
+  }
+}
+
+function describeFailed(message: string): RpcResponse<never> {
+  return {
+    rpcId: 'settings-document-failed' as never,
+    result: { ok: false, error: { code: 'internal', message, details: {} } },
+  }
+}
+
+describe('SettingsDocumentStore', () => {
+  it('loads provider metadata and asks the settings domain to open its document', async () => {
+    const describe = vi.fn(() => Promise.resolve(response(true)))
+    const openDocument = vi.fn(() => Promise.resolve(opened()))
+    const controller = new SettingsDocumentStore({ settings: { describe, openDocument } } as never)
+    await controller.load()
+    expect(controller.store.getSnapshot()).toEqual({
+      status: 'ready', opening: false, error: null,
+    })
+    await controller.open()
+    expect(openDocument).toHaveBeenCalledWith({})
+  })
+
+  it('marks absent or failed metadata unavailable without opening anything', async () => {
+    const openDocument = vi.fn(() => Promise.resolve(opened()))
+    const absent = new SettingsDocumentStore({
+      settings: { describe: () => Promise.resolve(response()), openDocument },
+    } as never)
+    await absent.load()
+    await absent.open()
+    expect(absent.store.getSnapshot().status).toBe('unavailable')
+    expect(openDocument).not.toHaveBeenCalled()
+
+    const failed = new SettingsDocumentStore({
+      settings: { describe: () => Promise.reject(new Error('offline')), openDocument },
+    } as never)
+    await failed.load()
+    expect(failed.store.getSnapshot()).toMatchObject({ status: 'unavailable', error: 'offline' })
+
+    const rejected = new SettingsDocumentStore({
+      settings: { describe: () => Promise.resolve(describeFailed('provider failed')), openDocument },
+    } as never)
+    await rejected.load()
+    expect(rejected.store.getSnapshot()).toMatchObject({
+      status: 'unavailable', error: 'provider failed',
+    })
+  })
+
+  it('collapses concurrent open gestures and recovers after a failure', async () => {
+    let resolveOpen!: (response: RpcResponse<{ opened: true }>) => void
+    const openDocument = vi.fn(() => new Promise<RpcResponse<{ opened: true }>>((resolve) => { resolveOpen = resolve }))
+    const controller = new SettingsDocumentStore({
+      settings: { describe: () => Promise.resolve(response(true)), openDocument },
+    } as never)
+    await controller.load()
+    const first = controller.open()
+    const second = controller.open()
+    expect(openDocument).toHaveBeenCalledOnce()
+    resolveOpen({
+      rpcId: 'settings-open-failed' as never,
+      result: { ok: false, error: { code: 'internal', message: 'no default editor', details: {} } },
+    })
+    await Promise.all([first, second])
+    expect(controller.store.getSnapshot()).toMatchObject({
+      status: 'ready', opening: false, error: 'no default editor',
+    })
+  })
+
+  it('ignores stale metadata completions and reports non-Error native failures', async () => {
+    let resolveFirst!: (value: ReturnType<typeof response>) => void
+    const first = new Promise<ReturnType<typeof response>>((resolve) => { resolveFirst = resolve })
+    const describe = vi.fn()
+      .mockReturnValueOnce(first)
+      .mockResolvedValueOnce(response(true))
+    let rejectOpen!: (reason?: unknown) => void
+    const controller = new SettingsDocumentStore({
+      settings: {
+        describe,
+        openDocument: () => new Promise((_, reject) => { rejectOpen = reject }),
+      },
+    } as never)
+    const stale = controller.load()
+    await controller.load()
+    resolveFirst(response())
+    await stale
+    expect(controller.store.getSnapshot().status).toBe('ready')
+    const opening = controller.open()
+    rejectOpen('native unavailable')
+    await opening
+    expect(controller.store.getSnapshot()).toMatchObject({
+      status: 'ready', opening: false, error: 'native unavailable',
+    })
+
+    let rejectFirst!: (error: Error) => void
+    const rejectedFirst = new Promise<ReturnType<typeof response>>((_, reject) => { rejectFirst = reject })
+    const caught = new SettingsDocumentStore({
+      settings: {
+        describe: vi.fn()
+          .mockReturnValueOnce(rejectedFirst)
+          .mockResolvedValueOnce(response(true)),
+        openDocument: vi.fn(),
+      },
+    } as never)
+    const staleRejection = caught.load()
+    await caught.load()
+    rejectFirst(new Error('stale offline'))
+    await staleRejection
+    expect(caught.store.getSnapshot()).toMatchObject({ status: 'ready', error: null })
+  })
+})