[ImgBot] Optimize images

*Total -- 603.18kb -> 534.83kb (11.33%)

/src/assets/img/user.png -- 27.01kb -> 12.71kb (52.93%)
/public/icons/openai.png -- 91.88kb -> 71.87kb (21.78%)
/src/assets/img/ai.png -- 415.48kb -> 383.83kb (7.62%)
/public/icons/groq.png -- 1.42kb -> 1.35kb (4.9%)
/public/icons/google.png -- 67.40kb -> 65.07kb (3.46%)

Signed-off-by: ImgBotApp <ImgBotHelp@gmail.com>

Author: ImgBotApp