TTS: add missing OpenAI voices (ballad, cedar, juniper, marin, verse) (openclaw#11020) thanks @lailoo

Verified:
- pnpm install --frozen-lockfile
- pnpm build
- pnpm check
- pnpm test

Co-authored-by: ${pr_author_login} <${coauthor_email}>
Co-authored-by: ${tak_name} <${tak_email}>

src/tts/tts.test.ts

@@ -97,6 +97,14 @@ describe("tts", () => {
       }
     });
 
+    it("includes newer OpenAI voices (ballad, cedar, juniper, marin, verse) (#2393)", () => {
+      expect(isValidOpenAIVoice("ballad")).toBe(true);
+      expect(isValidOpenAIVoice("cedar")).toBe(true);
+      expect(isValidOpenAIVoice("juniper")).toBe(true);
+      expect(isValidOpenAIVoice("marin")).toBe(true);
+      expect(isValidOpenAIVoice("verse")).toBe(true);
+    });
+
     it("rejects invalid voice names", () => {
       expect(isValidOpenAIVoice("invalid")).toBe(false);
       expect(isValidOpenAIVoice("")).toBe(false);