Expand voice presets to 8 voices (3 female, 5 male)

All transcribed via whisper-medium. Sources: Chatterbox demo GCS bucket
(ResembleAI) and F5-TTS repo (SWivid).

Female: Shadowheart, American actress, Podcast host
Male: Nature, Old Hollywood, Rick Sanchez, Stewie Griffin,
      Harvey Keitel, Conan O'Brien

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

workflows/voice_cloning.json

@@ -29,7 +29,7 @@
         {"name": "ref_text",  "type": "STRING", "links": [3], "shape": 3, "slot_index": 1}
       ],
       "properties": {"Node name for S&R": "OmniVoiceVoicePreset"},
-      "widgets_values": ["Nature – female, warm (F5-TTS ref)"]
+      "widgets_values": ["Shadowheart – female, expressive (Chatterbox)"]
     },
     {
       "id": 3,