refactor(chat): route browser chat through one runtime (P3 Slice-Zero Task 5) (#1172)

Co-authored-by: shaggy <[email protected]>

apps/gateway/src/harness/harness.module.ts

@@ -1,7 +1,12 @@
 import { Module } from '@nestjs/common';
 import { HarnessRegistry } from './harness.registry.js';
 import { HarnessService } from './harness.service.js';
-import { HARNESS_REGISTRY, HARNESS_SERVICE } from './harness.tokens.js';
+import {
+  HARNESS_CONVERSATION_SERVICE,
+  HARNESS_CONVERSATION_SERVICE_UNAVAILABLE,
+  HARNESS_REGISTRY,
+  HARNESS_SERVICE,
+} from './harness.tokens.js';
 import { HarnessController } from './harness.controller.js';
 import { HarnessSelectionController } from './harness-selection.controller.js';
 import { HarnessSelectionService } from './harness-selection.service.js';
@@ -20,9 +25,13 @@ import { HarnessSelectionRepository } from './harness-selection.repository.js';
   providers: [
     { provide: HARNESS_REGISTRY, useFactory: () => new HarnessRegistry() },
     { provide: HARNESS_SERVICE, useClass: HarnessService },
+    // Task Five: bind the conversation-service token to its explicit "not yet bound"
+    // sentinel. The pi-rpc router treats this as a hard, typed startup failure; Task 14
+    // replaces it with a real service. Exported so ChatModule's router can inject it.
+    { provide: HARNESS_CONVERSATION_SERVICE, useValue: HARNESS_CONVERSATION_SERVICE_UNAVAILABLE },
     HarnessSelectionRepository,
     HarnessSelectionService,
   ],
-  exports: [HARNESS_REGISTRY, HARNESS_SERVICE],
+  exports: [HARNESS_REGISTRY, HARNESS_SERVICE, HARNESS_CONVERSATION_SERVICE],
 })
 export class HarnessModule {}