feat: agent routing engine — cost/capability matrix (P2-003) (#75)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

apps/gateway/src/agent/agent.module.ts

@@ -1,12 +1,13 @@
 import { Global, Module } from '@nestjs/common';
 import { AgentService } from './agent.service.js';
 import { ProviderService } from './provider.service.js';
+import { RoutingService } from './routing.service.js';
 import { ProvidersController } from './providers.controller.js';
 
 @Global()
 @Module({
-  providers: [ProviderService, AgentService],
+  providers: [ProviderService, RoutingService, AgentService],
   controllers: [ProvidersController],
-  exports: [AgentService, ProviderService],
+  exports: [AgentService, ProviderService, RoutingService],
 })
 export class AgentModule {}