#14 task create: --body/--column flags (feature)

task create is title-only; body + column are file edits after. Add --body and --column (todo|doing|blocked|done per spec §task); update spec/schema.md + fixtures + -h within budget. Acceptance: 'f0rge task create --title X --body B --column doing' → task with body, status doing, correct column in list; budgets hold.