onnxRuntimeGenAI.QNN Long-Term Inference Crash and Memory Anomalies Issue Report

# Bug Description and Reproduction
## Describe the Bug
When using onnxRuntimeGenAI.QNN for long-term inference, multiple machines crash after 1-2 hours of continuous inference. Even if they survive this duration, issues such as garbled responses or no responses will occur.

```

Application: dynabook Assistant.exe
CoreCLR Version: 8.0.1925.36514
.NET Version: 8.0.19
Description: The process was terminated due to an unhandled exception.
Exception Info: System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
Stack:
at Microsoft.ML.OnnxRuntimeGenAI.NativeMethods.OgaTokenizerEncode(IntPtr, Byte[], IntPtr)
at Microsoft.ML.OnnxRuntimeGenAI.NativeMethods.OgaTokenizerEncode(IntPtr, Byte[], IntPtr)
at Microsoft.ML.OnnxRuntimeGenAI.Tokenizer.Encode(System.String)
at Microsoft.ML.OnnxRuntimeGenAI.OnnxRuntimeGenAIChatClient+d__13.MoveNext()
at System.Runtime.CompilerServices.AsyncMethodBuilderCore.Start[[System.__Canon, System.Private.CoreLib, Version=8.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]](System.__Canon ByRef)
at Microsoft.ML.OnnxRuntimeGenAI.OnnxRuntimeGenAIChatClient+d__13.System.Collections.Generic.IAsyncEnumerator.MoveNextAsync()
at dynabookSmartHelp.LLMProvider.OnnxRuntimeGenAI+<>c__DisplayClass19_0+<b__1>d.MoveNext()
at System.Runtime.CompilerServices.AsyncMethodBuilderCore.Start[[System.__Canon, System.Private.CoreLib, Version=8.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]](System.__Canon ByRef)
at dynabookSmartHelp.LLMProvider.OnnxRuntimeGenAI+<>c__DisplayClass19_0.b__1()
at System.Threading.Tasks.Task`1[[System.__Canon, System.Private.CoreLib, Version=8.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].InnerInvoke()
at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(System.Threading.Thread, System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)
at System.Threading.Tasks.Task.ExecuteWithThreadLocal(System.Threading.Tasks.Task ByRef, System.Threading.Thread)
at System.Threading.ThreadPoolWorkQueue.Dispatch()
at System.Threading.PortableThreadPool+WorkerThread.WorkerThreadStart()
```

## To Reproduce
Steps to reproduce the issue:
1. Initialize the model
2. Repeat the inference process (Start inference → Wait for inference to end → Start inference)

## Expected Behavior
No application crashes.

## Desktop (please complete the following information)
- OS: Windows 11 Home 25H2 26200.6588
- OnnxRuntimeGenAI.QNN: 0.10.0
- NPU Driver: 30.0.140.1000/30.0.145.1000

## Additional Context
Add any other relevant information about the issue here.

Start by reproducing repeated inference on Windows 11 with onnxRuntimeGenAI.QNN 0.10.0 and the listed NPU drivers, while watching for crashes, garbled responses, or missing responses. Trace the reported NativeMethods.OgaTokenizerEncode and Tokenizer.Encode calls in the crash stack; done means continuous inference no longer crashes or produces the reported anomalies.

Written by the indexing model from the issue text.