This refactor standardizes how related inventory, purchasing, manufacturing, and sales stock records are grouped internally. It reduces code complexity and helps prevent subtle mismatches in stock and procurement processing, with no intended change to day-to-day user workflows.

Instead of using sort + groupby of itertools (which group only
consecutive), use only the groupby of odoo.tools which
decrease the complexity of the code and avoid unmatched keys
between sort keys and groupby keys

task-2648449