feat(orchestrator): add SSE events, queue controls, and mosaic rails sync

apps/orchestrator/src/api/agents/agent-events.service.ts

@@ -0,0 +1,70 @@
+import { Injectable, Logger, OnModuleInit } from "@nestjs/common";
+import { randomUUID } from "crypto";
+import { ValkeyService } from "../../valkey/valkey.service";
+import type { EventHandler, OrchestratorEvent } from "../../valkey/types";
+
+type UnsubscribeFn = () => void;
+
+@Injectable()
+export class AgentEventsService implements OnModuleInit {
+  private readonly logger = new Logger(AgentEventsService.name);
+  private readonly subscribers = new Map<string, EventHandler>();
+  private connected = false;
+
+  constructor(private readonly valkeyService: ValkeyService) {}
+
+  async onModuleInit(): Promise<void> {
+    if (this.connected) return;
+
+    await this.valkeyService.subscribeToEvents(
+      (event) => {
+        this.subscribers.forEach((handler) => {
+          void handler(event);
+        });
+      },
+      (error, _raw, channel) => {
+        this.logger.warn(`Event stream parse/validation warning on ${channel}: ${error.message}`);
+      }
+    );
+
+    this.connected = true;
+    this.logger.log("Agent event stream subscription active");
+  }
+
+  subscribe(handler: EventHandler): UnsubscribeFn {
+    const id = randomUUID();
+    this.subscribers.set(id, handler);
+    return () => {
+      this.subscribers.delete(id);
+    };
+  }
+
+  async getInitialSnapshot(): Promise<{
+    type: "stream.snapshot";
+    timestamp: string;
+    agents: number;
+    tasks: number;
+  }> {
+    const [agents, tasks] = await Promise.all([
+      this.valkeyService.listAgents(),
+      this.valkeyService.listTasks(),
+    ]);
+
+    return {
+      type: "stream.snapshot",
+      timestamp: new Date().toISOString(),
+      agents: agents.length,
+      tasks: tasks.length,
+    };
+  }
+
+  createHeartbeat(): OrchestratorEvent {
+    return {
+      type: "task.processing",
+      timestamp: new Date().toISOString(),
+      data: {
+        heartbeat: true,
+      },
+    };
+  }
+}