refactor(bluebubbles): share multipart helpers

extensions/bluebubbles/src/chat.ts

@@ -2,6 +2,7 @@ import type { OpenClawConfig } from "openclaw/plugin-sdk";
 import crypto from "node:crypto";
 import path from "node:path";
 import { resolveBlueBubblesAccount } from "./accounts.js";
+import { postMultipartFormData } from "./multipart.js";
 import { getCachedBlueBubblesPrivateApiStatus } from "./probe.js";
 import { blueBubblesFetchWithTimeout, buildBlueBubblesApiUrl } from "./types.js";
 
@@ -376,26 +377,12 @@ export async function setGroupIconBlueBubbles(
   // Close multipart body
   parts.push(encoder.encode(`--${boundary}--\r\n`));
 
-  // Combine into single buffer
-  const totalLength = parts.reduce((acc, part) => acc + part.length, 0);
-  const body = new Uint8Array(totalLength);
-  let offset = 0;
-  for (const part of parts) {
-    body.set(part, offset);
-    offset += part.length;
-  }
-
-  const res = await blueBubblesFetchWithTimeout(
+  const res = await postMultipartFormData({
     url,
-    {
-      method: "POST",
-      headers: {
-        "Content-Type": `multipart/form-data; boundary=${boundary}`,
-      },
-      body,
-    },
-    opts.timeoutMs ?? 60_000, // longer timeout for file uploads
-  );
+    boundary,
+    parts,
+    timeoutMs: opts.timeoutMs ?? 60_000, // longer timeout for file uploads
+  });
 
   if (!res.ok) {
     const errorText = await res.text().catch(() => "");