feat(M6): Set up orchestrator service foundation

Add NestJS-based orchestrator service structure for M6-AgentOrchestration.

Changes:
- Migrate from Express to NestJS architecture
- Add health check endpoint module
- Add placeholder modules: coordinator, git, killswitch, monitor, queue, spawner, valkey
- Update configuration for NestJS
- Update lockfile for new dependencies

This is foundational work for M6-AgentOrchestration milestone.

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

apps/orchestrator/src/queue/queue.module.ts

@@ -0,0 +1,4 @@
+import { Module } from "@nestjs/common";
+
+@Module({})
+export class QueueModule {}