Update app.py

Widen cold-start allowance to 70s; cold boot measured up to 78s

Widen cold-start allowance to 45s after observing a 63s cold call

Fit GPU duration to measured pool timings; charge cold start once; cap steps at 12

Fix: Gradio 6 dropped show_api on event listeners

MiniMax-H3 Wushu Action LoRA demo