fix(#338): Add rate limiting to orchestrator API

- Add @nestjs/throttler for rate limiting support
- Configure multiple throttle profiles: default (100/min), strict (10/min for spawn/kill), status (200/min for polling)
- Apply strict rate limits to spawn and kill endpoints to prevent DoS
- Apply higher rate limits to status/health endpoints for monitoring
- Add OrchestratorThrottlerGuard with X-Forwarded-For support for proxy setups
- Add unit tests for throttler guard

Refs #338

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/orchestrator/src/api/health/health.module.ts

@@ -1,7 +1,9 @@
 import { Module } from "@nestjs/common";
 import { HealthController } from "./health.controller";
+import { HealthService } from "./health.service";
 
 @Module({
   controllers: [HealthController],
+  providers: [HealthService],
 })
 export class HealthModule {}