[ImgBot] Optimize images

*Total -- 1,524.12kb -> 1,352.07kb (11.29%)

/front/src/renderer/src/assets/models/cogito.png -- 18.88kb -> 9.31kb (50.7%)
/front/src/renderer/src/assets/mcp.png -- 39.70kb -> 29.10kb (26.69%)
/sample.png -- 56.56kb -> 45.70kb (19.21%)
/front/src/renderer/src/assets/agents/persian-assistant.png -- 1,408.98kb -> 1,267.96kb (10.01%)

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

Author: ImgBotApp