- trees.py: change account_id=current_user.account_id →
account_id=tree.account_id so super-admin cross-account shares land in
the tree's tenant where RLS will see them.
- migration a05e1a1bea7c: fix backfill to join tree_shares → trees instead
of tree_shares → users(created_by). Same logic: historical shares belong
to the tree's tenant.
- test_tree_sharing.py: add test_share_account_id_matches_tree_not_actor
to assert share.account_id == tree.account_id after POST /share; also
add missing account_id to all direct TreeShare(...) constructors in
existing tests.
- test_phase1_migrations.py: remove team_id= from TargetList constructor
(column dropped in Phase 3).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>