Install and wire CUDA runtime for Windows STT

python/loopback_stt_worker.py

@@ -2,13 +2,66 @@ import base64
 import json
 import os
 import sys
+import site
 import traceback
 from typing import Any
+from pathlib import Path
 
 import numpy as np
 from faster_whisper import WhisperModel
 
 
+def configure_windows_dll_search_paths() -> list[str]:
+    if sys.platform != "win32":
+        return []
+
+    candidates: list[Path] = []
+    executable_dir = Path(sys.executable).resolve().parent
+    venv_root = executable_dir.parent
+    candidates.extend(
+        [
+            venv_root / "Lib" / "site-packages" / "nvidia" / "cublas" / "bin",
+            venv_root / "Lib" / "site-packages" / "nvidia" / "cudnn" / "bin",
+        ]
+    )
+
+    for package_path in site.getsitepackages():
+        base = Path(package_path)
+        candidates.extend(
+            [
+                base / "nvidia" / "cublas" / "bin",
+                base / "nvidia" / "cudnn" / "bin",
+            ]
+        )
+
+    added: list[str] = []
+    seen: set[str] = set()
+    for candidate in candidates:
+        normalized = str(candidate.resolve())
+        if normalized in seen:
+            continue
+        seen.add(normalized)
+        if not candidate.exists():
+            continue
+
+        os.add_dll_directory(normalized)
+        if normalized not in os.environ.get("PATH", ""):
+            os.environ["PATH"] = normalized + os.pathsep + os.environ.get("PATH", "")
+        added.append(normalized)
+
+    return added
+
+
+os.environ.setdefault("HF_HUB_DISABLE_SYMLINKS_WARNING", "1")
+CONFIGURED_DLL_PATHS = configure_windows_dll_search_paths()
+if CONFIGURED_DLL_PATHS:
+    print(
+        f"configured CUDA DLL search paths: {', '.join(CONFIGURED_DLL_PATHS)}",
+        file=sys.stderr,
+        flush=True,
+    )
+
+
 def resolve_model() -> WhisperModel:
     model_name = os.environ.get("WHISPER_MODEL", "large-v3-turbo")
     requested_device = os.environ.get("WHISPER_DEVICE", "auto")