Add MT-LNN package and trained adapter checkpoint (500 steps, Qwen2.5-0.5B)

Switch to Qwen2.5-0.5B-Instruct: bilingual, faster, fix word-sticking decode

Fix Gradio 6.x: ssr_mode=False, server_name=0.0.0.0, move theme to launch()

Add MT-LNN Gradio demo app

initial commit