Preload cu13 NVRTC and default Whisper validation on

Force-load libnvrtc.so.13 and libnvrtc-builtins.so.13.0 at app startup
with RTLD_GLOBAL. Required because nvidia-cuda-nvrtc-cu12 (pulled in
transitively by nvidia-cudnn-cu12 for faster-whisper) creates
nvidia/cuda_nvrtc/, which torch's _preload_cuda_deps prefers over
nvidia/cu13/ and ends up loading the wrong nvrtc version — breaking
torch's JIT (e.g. Kokoro/voice cloning) with "failed to open
libnvrtc-builtins.so.13.0". Pre-resolving cu13 by absolute path makes
torch's later mistaken preload a no-op; cuDNN-cu12 still loads its own
libnvrtc.so.12 by versioned soname.

Also flip Whisper validation default to on across the three tabs.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app.py

@@ -5,6 +5,7 @@
 """Gradio web UI for Scenema Audio (ZeroGPU, single-process)."""
 
 import asyncio
+import ctypes
 import io
 import logging
 import os
@@ -15,6 +16,17 @@ import uuid
 from pathlib import Path
 from xml.sax.saxutils import escape
 
+# Preload cu13 NVRTC so torch's JIT (built against CUDA 13) finds its builtins.
+# nvidia-cuda-nvrtc-cu12 (transitive dep of nvidia-cudnn-cu12, installed for
+# faster-whisper) creates nvidia/cuda_nvrtc/, which torch's preload prefers over
+# nvidia/cu13/ — making torch load the wrong nvrtc version. RTLD_GLOBAL here puts
+# cu13 in memory first; cuDNN-cu12 still dlopens its own libnvrtc.so.12 by soname.
+_CU13_LIB = "/usr/local/lib/python3.12/site-packages/nvidia/cu13/lib"
+for _lib in ("libnvrtc-builtins.so.13.0", "libnvrtc.so.13"):
+    _path = os.path.join(_CU13_LIB, _lib)
+    if os.path.exists(_path):
+        ctypes.CDLL(_path, mode=ctypes.RTLD_GLOBAL)
+
 os.environ.setdefault("PYTORCH_CUDA_ALLOC_CONF", "expandable_segments:True")
 
 # ── Model paths ───────────────────────────────────────────────
@@ -631,7 +643,7 @@ def create_demo() -> gr.Blocks:
                             )
                             gen_validate = gr.Checkbox(
                                 label="Whisper Validation",
-                                value=False,
+                                value=True,
                                 interactive=True
                             )
                             gen_skip_vc = gr.Checkbox(
@@ -822,7 +834,7 @@ def create_demo() -> gr.Blocks:
                             )
                             vc_validate = gr.Checkbox(
                                 label="Whisper Validation",
-                                value=False,
+                                value=True,
                                 interactive=True,
                             )
                         vc_btn = gr.Button("Generate with Voice Cloning", variant="primary")
@@ -901,7 +913,7 @@ def create_demo() -> gr.Blocks:
                             )
                             raw_validate = gr.Checkbox(
                                 label="Whisper Validation",
-                                value=False,
+                                value=True,
                                 interactive=True,
                             )
                             raw_skip_vc = gr.Checkbox(