fix(#338): Add session cleanup on terminal states

- Add removeSession and scheduleSessionCleanup methods to AgentSpawnerService
- Schedule session cleanup after completed/failed/killed transitions
- Default 30 second delay before cleanup to allow status queries
- Implement OnModuleDestroy to clean up pending timers
- Add forwardRef injection to avoid circular dependency
- Add comprehensive tests for cleanup functionality

Refs #338

apps/orchestrator/src/spawner/agent-lifecycle.service.ts

@@ -1,5 +1,6 @@
-import { Injectable, Logger } from "@nestjs/common";
+import { Injectable, Logger, Inject, forwardRef } from "@nestjs/common";
 import { ValkeyService } from "../valkey/valkey.service";
+import { AgentSpawnerService } from "./agent-spawner.service";
 import type { AgentState, AgentStatus, AgentEvent } from "../valkey/types";
 import { isValidAgentTransition } from "../valkey/types/state.types";
 
@@ -18,7 +19,11 @@ import { isValidAgentTransition } from "../valkey/types/state.types";
 export class AgentLifecycleService {
   private readonly logger = new Logger(AgentLifecycleService.name);
 
-  constructor(private readonly valkeyService: ValkeyService) {
+  constructor(
+    private readonly valkeyService: ValkeyService,
+    @Inject(forwardRef(() => AgentSpawnerService))
+    private readonly spawnerService: AgentSpawnerService
+  ) {
     this.logger.log("AgentLifecycleService initialized");
   }
 
@@ -84,6 +89,9 @@ export class AgentLifecycleService {
     // Emit event
     await this.publishStateChangeEvent("agent.completed", updatedState);
 
+    // Schedule session cleanup
+    this.spawnerService.scheduleSessionCleanup(agentId);
+
     this.logger.log(`Agent ${agentId} transitioned to completed`);
     return updatedState;
   }
@@ -116,6 +124,9 @@ export class AgentLifecycleService {
     // Emit event
     await this.publishStateChangeEvent("agent.failed", updatedState, error);
 
+    // Schedule session cleanup
+    this.spawnerService.scheduleSessionCleanup(agentId);
+
     this.logger.error(`Agent ${agentId} transitioned to failed: ${error}`);
     return updatedState;
   }
@@ -147,6 +158,9 @@ export class AgentLifecycleService {
     // Emit event
     await this.publishStateChangeEvent("agent.killed", updatedState);
 
+    // Schedule session cleanup
+    this.spawnerService.scheduleSessionCleanup(agentId);
+
     this.logger.warn(`Agent ${agentId} transitioned to killed`);
     return updatedState;
   }