:recycle: [Refactor] Load js from cdn instead of local

:zap: [Enhance] Prettify user input region paddings

:gem: [Feature] Replace text with icon for buttons

:gem: [Feature] Separate Send and Regenerate, and bind enter event to send

:gem: [Feature] Place user-interactions at bottom, and set max-height of messagers-container adjustive to page scale ratio

:gem: [Feature] Support chat with selected llm models

:recycle: [Refactor] Clean llm_requester with imports from chat_operator

:recycle: [Refactor] Rename Concurrent Agents to LLM Mixer