Add internal/shopping with Generate(weekStart), one entry point for the first generation and every regeneration. It builds one group per plan day (dinner_id, date, position by date) and one item per ingredient of the dinner's recipe, in ingredient order, reusing the values recipe grounding stored: a fetched recipe's normalized name with qty and unit joined for display, or a manual recipe's line as typed with no qty. A day whose dinner has no recipe or no ingredients gets no group and is reported in Skipped. Regenerating keeps the id and needed flag of each item whose (dinner_id, name) is unchanged, matching repeated names in order; new items are needed and items no longer planned are removed. It is deterministic and makes no model call. A frozen list is refused. Migration 0016 makes shopping_lists.title nullable (never empty) so a list exists untitled until the AI titles it, and adds shopping_groups.date. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>