fix(googlechat): truncate approval card text on UTF-16 boundary (#96573)

truncateText sliced the approval card text paragraph with String.slice,
which can cut through an astral character's surrogate pair (e.g. an emoji
straddling the 1797-char limit), leaving a lone surrogate in the card
text sent to Google Chat.

Use truncateUtf16Safe from the plugin SDK so truncation never splits a
surrogate pair, keeping the '...' suffix and the existing length budget.

Adds tests asserting the truncated Command card text stays UTF-16 well
formed and that an astral character is preserved when it fits.

extensions/googlechat/src/approval-handler.runtime.test.ts

@@ -110,6 +110,45 @@ function createDeferred<T>(): {
   return { promise, reject, resolve };
 }
 
+type CardPayloadWithTextWidgets = {
+  cardsV2: Array<{
+    card: {
+      sections?: Array<{
+        header?: string;
+        widgets?: Array<{ textParagraph?: { text: string } }>;
+      }>;
+    };
+  }>;
+};
+
+function getTextParagraphText(payload: unknown, header: string): string {
+  const text = (payload as CardPayloadWithTextWidgets).cardsV2[0]?.card.sections?.find(
+    (section) => section.header === header,
+  )?.widgets?.[0]?.textParagraph?.text;
+  if (typeof text !== "string") {
+    throw new Error(`Expected ${header} text paragraph`);
+  }
+  return text;
+}
+
+function isUtf16WellFormed(value: string): boolean {
+  for (let index = 0; index < value.length; index += 1) {
+    const codeUnit = value.charCodeAt(index);
+    if (codeUnit >= 0xd800 && codeUnit <= 0xdbff) {
+      const nextCodeUnit = index + 1 < value.length ? value.charCodeAt(index + 1) : -1;
+      if (nextCodeUnit < 0xdc00 || nextCodeUnit > 0xdfff) {
+        return false;
+      }
+      index += 1;
+      continue;
+    }
+    if (codeUnit >= 0xdc00 && codeUnit <= 0xdfff) {
+      return false;
+    }
+  }
+  return true;
+}
+
 describe("googleChatApprovalNativeRuntime", () => {
   async function preparePendingDelivery(view = createPendingView()) {
     const nowMs = Date.now();
@@ -149,6 +188,31 @@ describe("googleChatApprovalNativeRuntime", () => {
     return { pendingPayload, plannedTarget, prepared, request, view };
   }
 
+  it("keeps truncated pending command card text UTF-16 well formed", async () => {
+    const view = createPendingView();
+    view.commandText = `${"a".repeat(1796)}😀${"b".repeat(100)}`;
+
+    const { pendingPayload } = await preparePendingDelivery(view);
+    const commandText = getTextParagraphText(pendingPayload, "Command");
+
+    expect(commandText.length).toBeLessThanOrEqual(1800);
+    expect(commandText.endsWith("...")).toBe(true);
+    expect(isUtf16WellFormed(commandText)).toBe(true);
+    expect(JSON.stringify(pendingPayload.cardsV2)).not.toContain("\\ud83d");
+  });
+
+  it("preserves a complete astral character when it fits before the truncation suffix", async () => {
+    const view = createPendingView();
+    view.commandText = `${"a".repeat(1795)}😀${"b".repeat(100)}`;
+
+    const { pendingPayload } = await preparePendingDelivery(view);
+    const commandText = getTextParagraphText(pendingPayload, "Command");
+
+    expect(commandText).toBe(`${"a".repeat(1795)}😀...`);
+    expect(commandText.length).toBe(1800);
+    expect(isUtf16WellFormed(commandText)).toBe(true);
+  });
+
   it("sends pending cards and updates the delivered message without buttons", async () => {
     sendGoogleChatMessage.mockResolvedValue({ messageName: "spaces/AAA/messages/msg-1" });
     updateGoogleChatMessage.mockResolvedValue({ messageName: "spaces/AAA/messages/msg-1" });

extensions/googlechat/src/approval-handler.runtime.ts

@@ -9,6 +9,7 @@ import { buildChannelApprovalNativeTargetKey } from "openclaw/plugin-sdk/approva
 import type { ExecApprovalDecision } from "openclaw/plugin-sdk/approval-runtime";
 import { createSubsystemLogger } from "openclaw/plugin-sdk/runtime-env";
 import { normalizeOptionalString } from "openclaw/plugin-sdk/string-coerce-runtime";
+import { truncateUtf16Safe } from "openclaw/plugin-sdk/text-utility-runtime";
 import { resolveGoogleChatAccount, type ResolvedGoogleChatAccount } from "./accounts.js";
 import { sendGoogleChatMessage, updateGoogleChatMessage } from "./api.js";
 import {
@@ -87,7 +88,7 @@ function escapeGoogleChatText(text: string): string {
 }
 
 function truncateText(text: string, maxChars = MAX_TEXT_PARAGRAPH_CHARS): string {
-  return text.length <= maxChars ? text : `${text.slice(0, maxChars - 3)}...`;
+  return text.length <= maxChars ? text : `${truncateUtf16Safe(text, maxChars - 3)}...`;
 }
 
 function buildMetadataText(metadata: readonly { label: string; value: string }[]): string {