refactor(session): centralize thread reset detection

Co-authored-by: Austin Mudd <austinm911@gmail.com>

src/web/auto-reply/session-snapshot.test.ts

@@ -0,0 +1,45 @@
+import fs from "node:fs/promises";
+import os from "node:os";
+import path from "node:path";
+
+import { describe, expect, it, vi } from "vitest";
+
+import { saveSessionStore } from "../../config/sessions.js";
+import { getSessionSnapshot } from "./session-snapshot.js";
+
+describe("getSessionSnapshot", () => {
+  it("uses heartbeat idle override while daily reset still applies", async () => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date(2026, 0, 18, 5, 0, 0));
+    try {
+      const root = await fs.mkdtemp(path.join(os.tmpdir(), "clawdbot-snapshot-"));
+      const storePath = path.join(root, "sessions.json");
+      const sessionKey = "agent:main:whatsapp:dm:S1";
+
+      await saveSessionStore(storePath, {
+        [sessionKey]: {
+          sessionId: "snapshot-session",
+          updatedAt: new Date(2026, 0, 18, 3, 30, 0).getTime(),
+        },
+      });
+
+      const cfg = {
+        session: {
+          store: storePath,
+          reset: { mode: "daily", atHour: 4, idleMinutes: 240 },
+          heartbeatIdleMinutes: 30,
+        },
+      } as Parameters<typeof getSessionSnapshot>[0];
+
+      const snapshot = getSessionSnapshot(cfg, "whatsapp:+15550001111", true, {
+        sessionKey,
+      });
+
+      expect(snapshot.resetPolicy.idleMinutes).toBe(30);
+      expect(snapshot.fresh).toBe(false);
+      expect(snapshot.dailyResetAt).toBe(new Date(2026, 0, 18, 4, 0, 0).getTime());
+    } finally {
+      vi.useRealTimers();
+    }
+  });
+});