Freeze ended weeks into the Supply archive and serve the archive API (Feature 17)

shopping.Freeze(weekStart) archives a week's Supply run once its week has
ended in the household's time zone, setting status archived and frozen_at;
it is idempotent, and a week not yet ended (ErrWeekNotEnded) or with no
list (ErrListNotFound) is an explicit error. A list still untitled is
titled first with archive_title and the same conditional write the
title_supply_run job uses; a failed title is logged and the list is
frozen untitled, keeping its week label.

GET /api/v1/shopping/archive?by=week|month|year returns the Supply runs
up to the household's current week, newest first, grouped by the
Monday's ISO week, month or year, each post with its week label, title or
null, dinner, item and on-hand counts, dinner names and current flag. Any
other by is 400 invalid_request. Frozen lists stay readable through
GET /shopping/{weekStart} and reject item PATCHes with 409 archived.

Maestro task 7ac36526-cb51-4dc7-bbad-6ebbee481942.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/db/shopping.sql.go

@@ -112,6 +112,28 @@ func (q *Queries) DeleteShoppingItem(ctx context.Context, id string) error {
 	return err
 }
 
+const freezeShoppingList = `-- name: FreezeShoppingList :execrows
+UPDATE shopping_lists
+SET status = 'archived', frozen_at = ?, updated_at = ?
+WHERE id = ? AND frozen_at IS NULL
+`
+
+type FreezeShoppingListParams struct {
+	FrozenAt  sql.NullString
+	UpdatedAt string
+	ID        string
+}
+
+// Freezes list id into the Supply archive at frozen_at, unless it is
+// frozen already.
+func (q *Queries) FreezeShoppingList(ctx context.Context, arg FreezeShoppingListParams) (int64, error) {
+	result, err := q.db.ExecContext(ctx, freezeShoppingList, arg.FrozenAt, arg.UpdatedAt, arg.ID)
+	if err != nil {
+		return 0, err
+	}
+	return result.RowsAffected()
+}
+
 const getShoppingItemList = `-- name: GetShoppingItemList :one
 SELECT shopping_lists.id, shopping_lists.week_start, shopping_lists.plan_id, shopping_lists.title, shopping_lists.status, shopping_lists.sent_to_chat_at, shopping_lists.frozen_at, shopping_lists.created_at, shopping_lists.updated_at
 FROM shopping_items
@@ -299,6 +321,47 @@ func (q *Queries) ListShoppingItems(ctx context.Context, listID string) ([]ListS
 	return items, nil
 }
 
+const listShoppingListsThrough = `-- name: ListShoppingListsThrough :many
+SELECT id, week_start, plan_id, title, status, sent_to_chat_at, frozen_at, created_at, updated_at FROM shopping_lists
+WHERE week_start <= ?
+ORDER BY week_start DESC
+`
+
+// The Supply runs of the weeks starting on or before week_start, newest
+// week first.
+func (q *Queries) ListShoppingListsThrough(ctx context.Context, weekStart string) ([]ShoppingList, error) {
+	rows, err := q.db.QueryContext(ctx, listShoppingListsThrough, weekStart)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var items []ShoppingList
+	for rows.Next() {
+		var i ShoppingList
+		if err := rows.Scan(
+			&i.ID,
+			&i.WeekStart,
+			&i.PlanID,
+			&i.Title,
+			&i.Status,
+			&i.SentToChatAt,
+			&i.FrozenAt,
+			&i.CreatedAt,
+			&i.UpdatedAt,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Close(); err != nil {
+		return nil, err
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
 const moveShoppingGroup = `-- name: MoveShoppingGroup :exec
 UPDATE shopping_groups
 SET position = ?, updated_at = ?