feat: expand chatbot width to 96% to improve visual space

refactor: reduce chatbot width to 70% and optimize vertical margins

fix: adjust chatbot card width and font size, increase badge font sizes

fix: align chatbot card widths, add round corners and increase font size by 3px

fix: resolve chatbot collapsed placeholder and tighten sidebar layout

fix: resolve UI layout overflow and dynamic sys path loading

style: optimize Gradio 6.x bubble chat layout and scrollbars

feat: optimize Gradio 6 CSS visual bubbles, add safe print overrides, and fix scraping matplotlib imports

fix: delete temporary css fix files and consolidate to ui_templates

feat: implement conversational hybrid RAG fallback routing and optimize presentation layout

refactor: gradio codes