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-theme/tests/invariant.client.spec.ts

@@ -0,0 +1,44 @@
+// @vitest-environment jsdom
+import { describe, expect, it } from 'vitest'
+import { Context } from '@deepseek-ai/cordis'
+import { apply as nodeApply } from '@deepseek-ai/dsh-client-ui-theme'
+import { apply as clientApply, inject, ThemeService } from '@deepseek-ai/dsh-client-ui-theme/client'
+import * as ThemeInvariant from '@deepseek-ai/dsh-client-ui-theme/invariant'
+import { apply as localeApply, inject as localeInject } from '@deepseek-ai/dsh-client-locale/client'
+import { SlotsService } from '@deepseek-ai/dsh-client-runtime/client'
+import InvariantService from '@deepseek-ai/dsh-invariants'
+import { stubSettingsScope } from '@deepseek-ai/dsh-client-test-runtime'
+
+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(ThemeInvariant).await()).resolves.toBeDefined()
+  })
+
+  it('node-half waits for optional Host services', () => {
+    nodeApply(new Context())
+    expect(true).toBe(true)
+  })
+
+  it('client apply provides ctx.theme over the slots/locale edges', async () => {
+    // The feature registers its own Appearance settings row with localized
+    // copy, hence the slots + locale edges.
+    expect(inject).toEqual(['slots', 'locale', 'connection', 'remote', 'settingsScope'])
+    const ctx = new Context()
+    new SlotsService(ctx)
+    ctx.provide('connection', {
+      api: { settings: { describe: () => Promise.resolve({
+        rpcId: 'theme-invariant' as never,
+        result: { ok: true, value: { writable: true, hasDocument: false, namespaces: [] } },
+      }) } },
+      isLoopback: true,
+    } as never)
+    // The settings row's transport and the forwarded-event port.
+    ctx.provide('remote', { $on: () => () => {} } as never)
+    ctx.provide('settingsScope', { bind: () => stubSettingsScope().scope } as never)
+    await ctx.plugin({ inject: localeInject, apply: localeApply }).await()
+    await ctx.plugin({ inject, apply: clientApply }).await()
+    expect(ctx.get('theme')).toBeInstanceOf(ThemeService)
+  })
+})