Add CLI flag for automated migration table updates in Supabase db pull

[ollebergkvist]

Is your feature request related to a problem? Please describe.
supabase db pull in automated scripts (like package.json pre-scripts), the command requires manual interaction to confirm migration history table updates. This breaks automation flows and CI/CD pipelines where user input isn't possible.

Describe the solution you'd like

• --auto-update-migrations=[yes|no] to automatically answer the "Update remote migration history table?" prompt
• Exit with code 0 when no schema changes are found
• Support for environment variables to control this behavior (e.g. SUPABASE_AUTO_UPDATE_MIGRATIONS)

Describe alternatives you've considered

• Shell scripting to pipe "y" responses

Additional context
This would enable seamless integration with development workflows and CI/CD pipelines.