Qwen QA Android example using ONNX Runtime

[dineshsoudagar]

This pull request adds a basic Android example for running Qwen2.5 and Qwen3 models using ONNX Runtime.

• Uses Hugging Face-style tokenizer.json with BPE.
• Includes a simple UI for question answering.
• Supports streaming inference with past key/value cache.
• Handles special tokens and prompt formatting for Qwen models.
• Designed to be easy to test and modify.

Tested on Android 14 with Qwen2.5-0.5B and Qwen3 ONNX models.

Let me know if any changes are needed, happy to improve it.

[dineshsoudagar]

@microsoft-github-policy-service agree