feat(tts): multi-voice switcher for EN & RU, Irina default voice, punctuation pause normalization and speed calibration

tests/test_api.py

@@ -2242,7 +2242,11 @@ def test_piper_tts_endpoints_and_caching():
     data = resp.json()
     assert "available" in data
     assert data["engine"] == "piper-vits"
-    assert "en_US-lessac" in data["voices"]
+    voice_ids = [v["id"] for v in data["voices"]]
+    assert "en_US-lessac" in voice_ids
+    assert "ru_RU-irina" in voice_ids
+    assert "en_US-ryan" in voice_ids
+    assert "en_GB-alan" in voice_ids
 
     # 2. Test TTS synthesis of English word
     tts_resp = client.get("/api/tts?text=Astronomy&lang=en&speed=1.0", headers=auth_headers)
@@ -2250,6 +2254,12 @@ def test_piper_tts_endpoints_and_caching():
     assert "audio/wav" in tts_resp.headers.get("content-type", "")
     assert len(tts_resp.content) > 1000
 
+    # 2b. Test TTS synthesis of Russian phrase with dash and Irina voice
+    ru_resp = client.get("/api/tts?text=Важный%20проект%20—%20он%20работает&lang=ru&voice=ru_RU-irina", headers=auth_headers)
+    assert ru_resp.status_code == 200
+    assert "audio/wav" in ru_resp.headers.get("content-type", "")
+    assert len(ru_resp.content) > 1000
+
     # 3. Test repeat request returns cached audio
     cached_resp = client.get("/api/tts?text=Astronomy&lang=en&speed=1.0", headers=auth_headers)
     assert cached_resp.status_code == 200