feat(FN-1085): align agent routing and runtime contracts

- Harden core AgentStore lifecycle behavior and heartbeat runtime integration paths
- Align dashboard agent APIs, server routes, and agent UI flows with the updated contract
- Tighten CLI agent/message command routing and validate payload handling semantics
- Expand test coverage across core, dashboard, engine, and CLI for route, heartbeat, and instruction regressions

packages/engine/src/runtimes/in-process-runtime.test.ts

@@ -352,6 +352,40 @@ describe("InProcessRuntime", () => {
         expect(scheduler!.getRegisteredAgents().length).toBeGreaterThanOrEqual(0);
       }
     });
+
+    it("routes assignment triggers through executeHeartbeat", async () => {
+      await runtime.start();
+
+      const monitor = runtime.getHeartbeatMonitor();
+      expect(monitor).toBeDefined();
+      const executeSpy = vi
+        .spyOn(monitor!, "executeHeartbeat")
+        .mockResolvedValue({ id: "run-test" } as any);
+
+      const store = (runtime as any).agentStore;
+      expect(store).toBeDefined();
+
+      const agent = await store.createAgent({
+        name: "Assignable",
+        role: "executor",
+      });
+
+      await store.assignTask(agent.id, "FN-001");
+
+      await vi.waitFor(() => {
+        expect(executeSpy).toHaveBeenCalledWith(
+          expect.objectContaining({
+            agentId: agent.id,
+            source: "assignment",
+            taskId: "FN-001",
+            contextSnapshot: expect.objectContaining({
+              taskId: "FN-001",
+              wakeReason: "assignment",
+            }),
+          }),
+        );
+      });
+    });
   });
 
   describe("configuration", () => {

packages/engine/src/runtimes/in-process-runtime.ts

@@ -234,14 +234,13 @@ export class InProcessRuntime
           async (agentId, source, context: WakeContext) => {
             if (!this.heartbeatMonitor) return;
 
-            // Convert WakeContext to WakeupOptions
-            const options = {
+            await this.heartbeatMonitor.executeHeartbeat({
+              agentId,
               source,
               triggerDetail: context.triggerDetail,
+              taskId: typeof context.taskId === "string" ? context.taskId : undefined,
               contextSnapshot: { ...context },
-            };
-
-            await this.heartbeatMonitor.startRun(agentId, options);
+            });
           },
         );
         this.triggerScheduler.start();
@@ -469,7 +468,7 @@ export class InProcessRuntime
   async executeHeartbeat(
     agentId: string,
     source: HeartbeatInvocationSource,
-    options?: { taskId?: string; triggerDetail?: string }
+    options?: { taskId?: string; triggerDetail?: string; contextSnapshot?: Record<string, unknown> }
   ): Promise<AgentHeartbeatRun | null> {
     if (this.status !== "active") {
       throw new Error(`Cannot execute heartbeat: runtime status is ${this.status}`);