Bird CLI doesn't support --since as a CLI flag.
Use X's search syntax: 'topic since:YYYY-MM-DD'
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
- is_bird_installed() checks if bird command is in PATH
- is_bird_authenticated() runs bird whoami to verify auth
- check_npm_available() checks if npm can install bird
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>