Revert "chore: update Space title/description and ignore .gstack"

chore: update Space title/description and ignore .gstack

add .gitignore, remove .gstack from tracking

remove index.html and style.css

remove app_file from README frontmatter

Update README.md

expand README with dataset, MCP server, and API docs

update org card UI and fix README demo link

initial commit: org card Space

initial commit