refactor: share gateway chat text normalization

src/gateway/server-chat.ts

@@ -390,12 +390,7 @@ export function createAgentEventHandler({
     nodeSendToSession(sessionKey, "chat", payload);
   };
 
-  const flushBufferedChatDeltaIfNeeded = (
-    sessionKey: string,
-    clientRunId: string,
-    sourceRunId: string,
-    seq: number,
-  ) => {
+  const resolveBufferedChatTextState = (clientRunId: string, sourceRunId: string) => {
     const bufferedText = stripInlineDirectiveTagsForDisplay(
       chatRunState.buffers.get(clientRunId) ?? "",
     ).text.trim();
@@ -407,6 +402,16 @@ export function createAgentEventHandler({
     const text = normalizedHeartbeatText.text.trim();
     const shouldSuppressSilent =
       normalizedHeartbeatText.suppress || isSilentReplyText(text, SILENT_REPLY_TOKEN);
+    return { text, shouldSuppressSilent };
+  };
+
+  const flushBufferedChatDeltaIfNeeded = (
+    sessionKey: string,
+    clientRunId: string,
+    sourceRunId: string,
+    seq: number,
+  ) => {
+    const { text, shouldSuppressSilent } = resolveBufferedChatTextState(clientRunId, sourceRunId);
     const shouldSuppressSilentLeadFragment = isSilentReplyLeadFragment(text);
     const shouldSuppressHeartbeatStreaming = shouldHideHeartbeatChatOutput(
       clientRunId,
@@ -453,17 +458,7 @@ export function createAgentEventHandler({
     error?: unknown,
     stopReason?: string,
   ) => {
-    const bufferedText = stripInlineDirectiveTagsForDisplay(
-      chatRunState.buffers.get(clientRunId) ?? "",
-    ).text.trim();
-    const normalizedHeartbeatText = normalizeHeartbeatChatFinalText({
-      runId: clientRunId,
-      sourceRunId,
-      text: bufferedText,
-    });
-    const text = normalizedHeartbeatText.text.trim();
-    const shouldSuppressSilent =
-      normalizedHeartbeatText.suppress || isSilentReplyText(text, SILENT_REPLY_TOKEN);
+    const { text, shouldSuppressSilent } = resolveBufferedChatTextState(clientRunId, sourceRunId);
     // Flush any throttled delta so streaming clients receive the complete text
     // before the final event. The 150 ms throttle in emitChatDelta may have
     // suppressed the most recent chunk, leaving the client with stale text.