Move packing slip / product bundle handling into
stock/doctype/delivery_note/services/packing.py:
- validate_packed_qty stays as a controller delegator (called via
hasattr contract in accounts/utils.py); has_unpacked_items stays
for onload/JS
- get_product_bundle_list and cancel_packing_slips move into the
service (internal-only; on_cancel repointed)
Pre-existing raw SQL in cancel_packing_slips moved verbatim.
No behaviour change.
e0e3dcc8bf