fix: add seed control_after_generate value to default workflow

ComfyUI appends a hidden "fixed"/"randomize" value after every INT
named "seed". Without it the widget values were misaligned.

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

workflows/omnivoice_voice_cloning.json

@@ -35,7 +35,7 @@
       "id": 3,
       "type": "OmniVoiceGenerate",
       "pos": [420, 80],
-      "size": {"0": 380, "1": 400},
+      "size": {"0": 380, "1": 430},
       "flags": {},
       "order": 2,
       "mode": 0,
@@ -54,7 +54,8 @@
         "",
         1.0,
         32,
-        42
+        42,
+        "fixed"
       ]
     },
     {