fix(slack): enable preview streaming in flat DMs (replyToMode: off) (#76330)

Summary:
- The PR enables Slack draft preview streaming for flat DMs in all non-off modes, updates Slack streaming tests/docs/config metadata/changelog, and refreshes small guard baselines.
- Reproducibility: yes. source-reproducible on current main: the helper returns false for `mode: "partial"` in ...  current test asserts that disabled path. I did not run tests because this review was explicitly read-only.

Automerge notes:
- Ran the ClawSweeper repair loop before final review.
- Included post-review commit in the final squash: fix(slack): enable preview streaming in flat DMs (replyToMode: off)
- Included post-review commit in the final squash: fix(clawsweeper): address review for automerge-openclaw-openclaw-5654…

Validation:
- ClawSweeper review passed for head 52e5d74ef9.
- Required merge gates passed before the squash merge.

Prepared head SHA: 52e5d74ef9
Review: https://github.com/openclaw/openclaw/pull/76330#issuecomment-4365017023

Co-authored-by: clawsweeper <274271284+clawsweeper[bot]@users.noreply.github.com>
Co-authored-by: bob <637186+HangGlidersRule@users.noreply.github.com>

extensions/slack/src/config-ui-hints.ts

@@ -111,7 +111,7 @@ export const slackChannelConfigUiHints = {
   },
   "streaming.nativeTransport": {
     label: "Slack Native Streaming",
-    help: "Enable native Slack text streaming (chat.startStream/chat.appendStream/chat.stopStream) when channels.slack.streaming.mode is partial (default: true). Requires a reply thread target; top-level DMs stay on the non-thread fallback path.",
+    help: "Enable native Slack text streaming (chat.startStream/chat.appendStream/chat.stopStream) when channels.slack.streaming.mode is partial (default: true). Native streaming and Slack assistant thread status require a reply thread target; top-level DMs can still use draft post-and-edit preview streaming.",
   },
   "streaming.preview.toolProgress": {
     label: "Slack Draft Tool Progress",

extensions/slack/src/monitor/message-handler/dispatch.streaming.test.ts

@@ -179,35 +179,44 @@ describe("slack native streaming thread hint", () => {
 });
 
 describe("slack preview streaming eligibility", () => {
-  it("stays on for room messages when streaming mode is enabled", () => {
+  it("stays off when streaming mode is disabled", () => {
     expect(
       shouldEnableSlackPreviewStreaming({
-        mode: "partial",
-        isDirectMessage: false,
-      }),
-    ).toBe(true);
-  });
-
-  it("stays off for top-level DMs without a reply thread", () => {
-    expect(
-      shouldEnableSlackPreviewStreaming({
-        mode: "partial",
-        isDirectMessage: true,
+        mode: "off",
       }),
     ).toBe(false);
   });
 
-  it("allows DM preview when the reply is threaded", () => {
+  it("stays on for room messages when streaming mode is enabled", () => {
     expect(
       shouldEnableSlackPreviewStreaming({
         mode: "partial",
-        isDirectMessage: true,
-        threadTs: "1000.1",
       }),
     ).toBe(true);
   });
 
-  it("keeps top-level DMs off even when replyToMode would create a reply thread", () => {
+  it("allows top-level DM draft previews without a reply thread", () => {
+    expect(
+      shouldEnableSlackPreviewStreaming({
+        mode: "partial",
+      }),
+    ).toBe(true);
+  });
+
+  it("allows non-partial draft preview modes", () => {
+    expect(
+      shouldEnableSlackPreviewStreaming({
+        mode: "block",
+      }),
+    ).toBe(true);
+    expect(
+      shouldEnableSlackPreviewStreaming({
+        mode: "progress",
+      }),
+    ).toBe(true);
+  });
+
+  it("keeps native streaming thread hints separate from draft preview eligibility", () => {
     const streamThreadHint = resolveSlackStreamingThreadHint({
       replyToMode: "all",
       incomingThreadTs: undefined,
@@ -218,10 +227,8 @@ describe("slack preview streaming eligibility", () => {
     expect(
       shouldEnableSlackPreviewStreaming({
         mode: "partial",
-        isDirectMessage: true,
-        threadTs: undefined,
       }),
-    ).toBe(false);
+    ).toBe(true);
     expect(streamThreadHint).toBe("1000.4");
   });
 });

extensions/slack/src/monitor/message-handler/dispatch.ts

@@ -117,16 +117,8 @@ export function isSlackStreamingEnabled(params: {
 
 export function shouldEnableSlackPreviewStreaming(params: {
   mode: "off" | "partial" | "block" | "progress";
-  isDirectMessage: boolean;
-  threadTs?: string;
 }): boolean {
-  if (params.mode === "off") {
-    return false;
-  }
-  if (!params.isDirectMessage) {
-    return true;
-  }
-  return Boolean(params.threadTs);
+  return params.mode !== "off";
 }
 
 export function shouldInitializeSlackDraftStream(params: {
@@ -446,8 +438,6 @@ export async function dispatchPreparedSlackMessage(prepared: PreparedSlackMessag
     !sourceRepliesAreToolOnly &&
     shouldEnableSlackPreviewStreaming({
       mode: slackStreaming.mode,
-      isDirectMessage: prepared.isDirectMessage,
-      threadTs: streamThreadHint,
     });
   const streamingEnabled =
     !sourceRepliesAreToolOnly &&