"""milestone-as-plan-container: milestones.body holds the plan/design

Revision ID: 0066
Revises: 0065
Create Date: 2026-06-14

T3 of plan #819. The milestone becomes the plan container: its `body` holds
the design/intent/purpose (markdown), `description` stays the one-liner, and
individual steps live as first-class child tasks (milestone_id) instead of
checkboxes crammed into a kind=plan task body. start_planning is reworked to
create a milestone instead of a kind=plan task (hard retirement going forward;
the 'plan' task_kind enum value stays valid so the historical plan-tasks are
left readable in place — no body-shredding backfill).

Schema change is just one nullable column; no data migration.
"""
from alembic import op
import sqlalchemy as sa


revision = "0066"
down_revision = "0065"
branch_labels = None
depends_on = None


def upgrade() -> None:
    op.add_column("milestones", sa.Column("body", sa.Text(), nullable=True))


def downgrade() -> None:
    op.drop_column("milestones", "body")