feat: unify gateway heartbeat

src/auto-reply/heartbeat.ts

@@ -0,0 +1,21 @@
+import { HEARTBEAT_TOKEN } from "./tokens.js";
+
+export const HEARTBEAT_PROMPT = "HEARTBEAT";
+
+export function stripHeartbeatToken(raw?: string) {
+  if (!raw) return { shouldSkip: true, text: "" };
+  const trimmed = raw.trim();
+  if (!trimmed) return { shouldSkip: true, text: "" };
+  if (trimmed === HEARTBEAT_TOKEN) return { shouldSkip: true, text: "" };
+  const hadToken = trimmed.includes(HEARTBEAT_TOKEN);
+  let withoutToken = trimmed.replaceAll(HEARTBEAT_TOKEN, "").trim();
+  if (hadToken && withoutToken) {
+    // LLMs sometimes echo malformed HEARTBEAT_OK_OK... tails; strip trailing OK runs to avoid spam.
+    withoutToken = withoutToken.replace(/[\s_]*OK(?:[\s_]*OK)*$/gi, "").trim();
+  }
+  const shouldSkip = withoutToken.length === 0;
+  return {
+    shouldSkip,
+    text: shouldSkip ? "" : withoutToken || trimmed,
+  };
+}