Settings: model section to top; default WebLLM + Qwen3 0.6B; copyable debug

Cache status + delete for WebLLM and Transformers.js (like wllama)

Fix Qwen3 on WebLLM: budget for thinking + capture reasoning_content

Fix Qwen3 parsing (/no_think) + WebLLM double-load guard & progress clarity

Fix model re-downloads (persistent storage) + WebLLM shader-f16 crash

Multi-engine benchmark: wllama vs Transformers.js vs WebLLM (engine selector)