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/runtime/tests/invariant.client.spec.ts

@@ -0,0 +1,49 @@
+/**
+ * Runtime invariant companion: the 'slots/changed' emission-order audit —
+ * a fired key must already carry a bumped version (emission follows the
+ * applied mutation), bogus payloads fail loud, foreign events pass.
+ */
+import { Context } from '@deepseek-ai/cordis'
+import { describe, expect, it } from 'vitest'
+import InvariantService from '@deepseek-ai/dsh-invariants'
+import * as RuntimeInvariant from '../src/invariant.ts'
+import { SlotsService } from '../src/client/slots.ts'
+
+async function setup(): Promise<Context> {
+  const ctx = new Context()
+  await ctx.plugin(InvariantService, { enabled: true })
+  await ctx.plugin(RuntimeInvariant).await()
+  return ctx
+}
+
+const emit = (ctx: Context, event: string, ...args: unknown[]): void => {
+  ;(ctx.emit as (event: string, ...args: unknown[]) => void)(event, ...args)
+}
+
+describe('runtime slots/changed invariant', () => {
+  it('passes foreign events and a legitimate mutation-then-emission sequence', async () => {
+    const ctx = await setup()
+    expect(() => { emit(ctx, 'unrelated/event', 'x') }).not.toThrow()
+    await ctx.plugin(SlotsService).await() // fiber must reach ACTIVE — the audit reads strict ctx.get
+    // A real registration bumps the version first and re-emits through
+    // onMutate — the audit sees version > 0 and stays quiet. (Erased call:
+    // the typed register face rides the wave-1 ui-slots types.)
+    const slots = ctx.slots as unknown as { register(options: object, component: unknown): () => void }
+    expect(() => slots.register({ name: 'root' }, () => null)).not.toThrow()
+  })
+
+  it('fails loud on a missing key and on an emission with no applied mutation', async () => {
+    const ctx = await setup()
+    expect(() => { emit(ctx, 'slots/changed', '') }).toThrow(/without a slot key/)
+    expect(() => { emit(ctx, 'slots/changed', 42) }).toThrow(/without a slot key/)
+    await ctx.plugin(SlotsService).await()
+    // Hand-emitted key that never saw a mutation: version 0 → violation.
+    expect(() => { emit(ctx, 'slots/changed', 'never-mutated') })
+      .toThrow(/before any mutation bumped its version/)
+  })
+
+  it('stays quiet when no slots service is mounted (nothing to audit against)', async () => {
+    const ctx = await setup()
+    expect(() => { emit(ctx, 'slots/changed', 'any-key') }).not.toThrow()
+  })
+})