[ImgBot] Optimize images (#3455)

*Total -- 1,383.25kb -> 1,231.27kb (10.99%)

/assets/apple-touch-icon.png -- 4.72kb -> 2.51kb (46.79%)
/assets/icons/256.png -- 4.72kb -> 2.51kb (46.79%)
/assets/title.png -- 6.63kb -> 3.80kb (42.73%)
/assets/favicon/favicon.png -- 6.83kb -> 3.93kb (42.45%)
/assets/icons/192.png -- 3.49kb -> 2.02kb (42.08%)
/assets/icons/128.png -- 2.29kb -> 1.50kb (34.81%)
/assets/about/ui.png -- 125.21kb -> 94.85kb (24.25%)
/assets/ai-orig.png -- 255.55kb -> 199.67kb (21.86%)
/assets/icons/64.png -- 1.21kb -> 0.99kb (18.34%)
/assets/about/drive.png -- 110.33kb -> 94.20kb (14.62%)
/assets/about/post.png -- 344.52kb -> 316.57kb (8.11%)
/assets/ai.png -- 243.43kb -> 234.93kb (3.49%)
/src/client/assets/pointer.png -- 274.33kb -> 273.80kb (0.19%)