Avoid illegal ZeroGPU duration defaults

app.py

@@ -66,10 +66,22 @@ def log_progress(message: str, level: int = 1, enabled: bool = True) -> None:
 load_dotenv()
 
 _GPU_DURATION = os.getenv("CHIZZLER_GPU_DURATION")
+_GPU_DURATION_MAX = os.getenv("CHIZZLER_GPU_DURATION_MAX")
 if _GPU_DURATION is not None:
-    DEFAULT_GPU_DURATION = int(_GPU_DURATION)
+    try:
+        DEFAULT_GPU_DURATION = int(_GPU_DURATION)
+    except ValueError:
+        DEFAULT_GPU_DURATION = 0
 else:
-    DEFAULT_GPU_DURATION = 3600 if os.getenv("SPACE_ID") else 0
+    DEFAULT_GPU_DURATION = 0
+
+if _GPU_DURATION_MAX is not None:
+    try:
+        max_duration = int(_GPU_DURATION_MAX)
+        if max_duration > 0:
+            DEFAULT_GPU_DURATION = min(DEFAULT_GPU_DURATION, max_duration)
+    except ValueError:
+        pass
 
 
 def gpu_decorator(duration: int):