refactor(faces): keep the generated contributions out of the Host aggregate

The Gateway and the carrier each compiled both halves under one tsconfig, so
the Host aggregate built their browser faces — including the face that owns
`ctx.remote`, the most likely future consumer of a generated `/remote`
contribution. Both packages now expose a host and a client face, and each
aggregate references only its own; three modules the halves share appear in
both file lists, as api/remotes already does.

The two apps/web specs in the Host aggregate restate the conversation engine's
Context key format instead of importing the Client runtime for it. A drift
makes the key miss its rendered node, so the assertion fails loudly.

The Host aggregate now reaches one Client project, the carrier's host face,
which the Gateway's own dispatch face needs; no generated contribution is
reachable from it.

apps/web/tests/chat-continuous-conversation.e2e.ts

@@ -12,14 +12,13 @@ import { afterAll, beforeAll, describe, expect, it, onTestFailed } from 'vitest'
 import { CallId, type StreamChunk } from '@deepseek-ai/dsh-llm'
 import type { ReplayEntry, ReplayOverrideDoc } from '@deepseek-ai/dsh-llm-replay'
 import type { SessionEvent, SessionId } from '@deepseek-ai/dsh-session'
-import { conversationContextKey } from '@deepseek-ai/dsh-client-runtime/client'
 import {
   launchWebScaffold,
   watchConsole,
   webSnapshotMode,
   type WebScaffold,
 } from './scaffold.ts'
-import { connectFreshWorkspace, newEnglishPage, saveFailureShot } from './support.ts'
+import { connectFreshWorkspace, conversationContextKey, newEnglishPage, saveFailureShot } from './support.ts'
 
 const MODE = webSnapshotMode()
 const TURN_COUNT = 12

apps/web/tests/chat-long-interactions.e2e.ts

@@ -11,7 +11,6 @@ import { afterAll, beforeAll, describe, expect, it, onTestFailed } from 'vitest'
 import type { StreamChunk } from '@deepseek-ai/dsh-llm'
 import type { ReplayEntry, ReplayOverrideDoc } from '@deepseek-ai/dsh-llm-replay'
 import { SessionId, type SessionEvent } from '@deepseek-ai/dsh-session'
-import { conversationContextKey } from '@deepseek-ai/dsh-client-runtime/client'
 import { createChatScrollFixture } from './chat-scroll-fixture.ts'
 import {
   launchWebScaffold,
@@ -20,7 +19,7 @@ import {
   webSnapshotMode,
   type WebScaffold,
 } from './scaffold.ts'
-import { newEnglishPage, saveFailureShot } from './support.ts'
+import { conversationContextKey, newEnglishPage, saveFailureShot } from './support.ts'
 
 const MODE = webSnapshotMode()
 const SESSION_ID = 'chat-long-interactions-e2e'

apps/web/tests/support.ts

@@ -119,3 +119,17 @@ export async function saveFailureShot(page: Page, name: string): Promise<void> {
     // Best-effort evidence: a dead page/browser at failure time must not mask the real assertion error.
   }
 }
+
+/**
+ * The conversation engine's Context key format, restated here rather than
+ * imported: these specs live in the Host compiler aggregate, which must not
+ * reach the Client plane. The engine's own copy is
+ * `conversationContextKey` in dsh-client-runtime; a drift between them makes
+ * the key miss its rendered node, so the assertion fails loudly.
+ * @param kind - Definition kind.
+ * @param id - Definition-local business identity.
+ * @returns the engine-owned Context key.
+ */
+export function conversationContextKey(kind: string, id: string): string {
+  return `${kind.length}:${kind}${id}`
+}