[ImgBot] Optimize images

*Total -- 7,351.02kb -> 6,875.59kb (6.47%)

/static/feishu.jpg -- 40.01kb -> 29.55kb (26.14%)
/static/studio_ui.png -- 303.60kb -> 268.96kb (11.41%)
/static/book-photo.jpg -- 6,257.38kb -> 5,835.05kb (6.75%)
/static/langgraph-poster.jpg -- 435.21kb -> 428.44kb (1.55%)
/static/langchain-poster.jpg -- 314.82kb -> 313.59kb (0.39%)

Signed-off-by: ImgBotApp <[email protected]>

Author: ImgBotApp