feat(chat): add Edge TTS playback

src/components/chat/speechStartOptions.test.ts

@@ -0,0 +1,31 @@
+import {
+  findSpeechSelectionStartOffset,
+  splitSpeechTextIntoChunks,
+} from "./speechStartOptions";
+
+describe("findSpeechSelectionStartOffset", () => {
+  it("finds the reading start from selected reply text", () => {
+    const text = "第一段内容。\n\n第二段  包含空格。\n第三段内容。";
+
+    expect(findSpeechSelectionStartOffset(text, "第二段 包含空格")).toBe(
+      text.indexOf("第二段"),
+    );
+    expect(findSpeechSelectionStartOffset(text, "第三段")).toBe(text.indexOf("第三段"));
+    expect(findSpeechSelectionStartOffset(text, "不存在")).toBeNull();
+  });
+});
+
+describe("splitSpeechTextIntoChunks", () => {
+  it("splits long text into bounded chunks", () => {
+    const text = Array.from({ length: 80 }, (_, index) => `第${index}句内容足够长。`).join("");
+    const chunks = splitSpeechTextIntoChunks(text);
+
+    expect(chunks.length).toBeGreaterThan(1);
+    expect(chunks.every((chunk) => chunk.length <= 520)).toBe(true);
+    expect(chunks.join("")).toBe(text);
+  });
+
+  it("keeps short text as one chunk", () => {
+    expect(splitSpeechTextIntoChunks("短句。")).toEqual(["短句。"]);
+  });
+});