[Hexagon:Feature] Support Qwen3-VL with symmetric and asymmetric block-wise quantization

[yydhYYDH]

Description

This change adds two main capabilities to the Android Hexagon backend:

• Qwen3-VL Vision model execution;
• symmetric and asymmetric block-wise INT4/INT8 quantization for Vision and language-model weights.

Performance

llm_bench -p N -n 128 -rep 3 on OnePlus 13 / Snapdragon 8 Elite / Hexagon v79, tokens/s:

Weight format	Prefill 128	Prefill 256	Prefill 512	Decode avg
INT4 asymmetric block64	893.07	1257.30	1417.40	18.06
INT8 symmetric block64	631.46	713.35	732.10	20.86
INT8 asymmetric block64	597.42	691.14	730.40	11.57
FP16	350.42	502.68	609.72	4.02

Module

Hexagon

Type

• Feature
• Bugfix
• Perf
• Refact
• Style
• Doc
• Test
• Chore

Checklist

• Commit message follows [Module:Type] Description format
• Code compiles without errors
• Tested on relevant platform(s)
• No unrelated format or style changes included