replaced MiniCPM5-1B with MiniCPM4.1-8B

updated model from MiniCPM3 to MiniCPM5

colors fixes; updated README

Run a local small model (MiniCPM3-4B via llama.cpp) instead of a cloud API

Fix dark-mode color clash by overriding Gradio design tokens

Move to Gradio 6, fix Space YAML, improve readability

Initial Gradio Space