The INSERT into template_trees incorrectly referenced `tags` as a column
on the `trees` table. Tags are a relationship via the `tree_tag_assignments`
join table — there is no direct column. Migration was failing with:
UndefinedColumn: column "tags" does not exist ... FROM trees
Fixed by replacing COALESCE(tags, '[]') with a correlated subquery that
aggregates tag names from tree_tag_assignments → tree_tags.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
The tags column was accidentally omitted from the is_default tree copy.
Now uses COALESCE(tags, '[]'::jsonb) to preserve source tree tags.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Creates template_trees and platform_steps (no account_id, no RLS).
Migrates is_default=TRUE trees and public steps into them.
Creates sentinel platform account (00000000-...-0001) for global
tree_categories, tree_tags, step_categories, step_library, and
is_default trees — clearing all NULL account_id rows in those tables
as prerequisite for Group 9 SET NOT NULL.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
