v0.21.1

Changelog

• 02b1305 chore(assets): consolidate demo GIF and remove unused assets
• 82c63ed docs(agents): add cast to GIF conversion command
• bb88edd feat(release): bump version to v0.21.1
• 460a50d feat(repl): move mode chip to input border and add plan mode styling
• 675dbe0 feat(repl): refresh status bar glyphs and layout