By activity (computed)
Active = at least one open task. Idle = no open tasks but project is still open. Done = project is archived/closed. No new fields needed.
Status columns, but each project is a full card with progress bar, %, hours, and task count.
Same card design either way; this just determines column placement.
My recommendation: Option 1 β by activity. Zero new fields, columns reflect reality automatically, and it matches what the screenshot already shows ("S29824 has 50 tasks, others have 0").