perf(test): fold session key utils into routing session key suite

src/routing/session-key.test.ts

@@ -1,4 +1,5 @@
 import { describe, expect, it } from "vitest";
+import { getSubagentDepth, isCronSessionKey } from "../sessions/session-key-utils.js";
 import { classifySessionKeyShape } from "./session-key.js";
 
 describe("classifySessionKeyShape", () => {
@@ -39,3 +40,33 @@ describe("session key backward compatibility", () => {
     expect(classifySessionKeyShape("agent:main:discord:direct:user123")).toBe("agent");
   });
 });
+
+describe("getSubagentDepth", () => {
+  it("returns 0 for non-subagent session keys", () => {
+    expect(getSubagentDepth("agent:main:main")).toBe(0);
+    expect(getSubagentDepth("main")).toBe(0);
+    expect(getSubagentDepth(undefined)).toBe(0);
+  });
+
+  it("returns 1 for depth-1 subagent session keys", () => {
+    expect(getSubagentDepth("agent:main:subagent:123")).toBe(1);
+  });
+
+  it("returns 2 for nested subagent session keys", () => {
+    expect(getSubagentDepth("agent:main:subagent:parent:subagent:child")).toBe(2);
+  });
+});
+
+describe("isCronSessionKey", () => {
+  it("matches base and run cron agent session keys", () => {
+    expect(isCronSessionKey("agent:main:cron:job-1")).toBe(true);
+    expect(isCronSessionKey("agent:main:cron:job-1:run:run-1")).toBe(true);
+  });
+
+  it("does not match non-cron sessions", () => {
+    expect(isCronSessionKey("agent:main:main")).toBe(false);
+    expect(isCronSessionKey("agent:main:subagent:worker")).toBe(false);
+    expect(isCronSessionKey("cron:job-1")).toBe(false);
+    expect(isCronSessionKey(undefined)).toBe(false);
+  });
+});