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

@@ -0,0 +18,4 @@
+    // -------------------------------------------------------------------------
+    describe("defaults", () => {
+        const cases: Array<{ name: string; error: HttpError; status: number; code: ErrorCode }> = [
+            { name: "ValidationError",      error: new ValidationError("bad"),  status: 400, code: ErrorCode.VALIDATION_FAILED },

@@ -0,0 +50,4 @@
+ */
+export class ShoppingListHandler {
+    constructor(
+        private readonly lists: ShoppingListRepository,

@@ -0,0 +94,4 @@
+        if (!list) throw new NotFoundError(LIST_NOT_FOUND);
+
+        // Any access level may read
+        const permission: ShoppingListEffectivePermission = this.permissionHelper.resolve(list, userId);

@@ -0,0 +73,4 @@
+    const openIds: Set<string> = new Set(open.map((item: ShoppingListItemEntity): string => item.id!));
+
+    // Named open items first, in request order; a Set keeps the first occurrence only
+    const named: Set<string> = new Set(requested.filter((id: string): boolean => openIds.has(id)));

@@ -0,0 +96,4 @@
+ */
+export class ShoppingListItemHandler {
+    constructor(
+        private readonly lists: ShoppingListRepository,

@@ -0,0 +277,4 @@
+                const locked: Set<Uuid> = await lists.lockLists([sourceListId, targetListId]);
+
+                // Re-read under the lock; if another move changed its list, lock that one next
+                const item: ShoppingListItemEntity = await this.findItemOrNotFound(items, itemId);

@@ -0,0 +476,4 @@
+    }
+
+    /** Trims an optional text; empty or absent becomes null. */
+    private trimToNull(value: string | null | undefined): string | null {

@@ -0,0 +6,4 @@
+ * Raw user columns as a SQL projection returns them, e.g. the owner columns of the
+ * shopping list overview query.
+ */
+export interface CompactUserColumns {

@@ -0,0 +9,4 @@
+ * One-way: items are changed through dedicated request types (add, edit, tick, …), never
+ * by sending an item DTO back, so the reverse direction does not exist.
+ *
+ * Optional values are absent keys, not null, as the contract says: `amount`, `unit` and

@@ -25,3 +36,3 @@
     dto.lastName = entity.lastName;
     dto.role = entity.role;
-    dto.avatarUrl = entity.avatarKey ? `${IMAGE_BASE_ROUTE}/${entity.avatarKey}` : null;
+    dto.avatarUrl = avatarUrlFor(entity.avatarKey);

@@ -0,0 +147,4 @@
+    // ---------------------------------------------------------------------------
+
+    /**
+     * W1 — inserts a new, open item. The database sets `version` to 1.

@@ -0,0 +72,4 @@
+                .createQueryBuilder(ShoppingListEntity, LIST_ALIAS)
+                .select(`${LIST_ALIAS}.id`)
+                .where(`${LIST_ALIAS}.id = :id`, { id })
+                .setLock("pessimistic_write")

@@ -0,0 +6,4 @@
+/** Repositories bound to one transaction's EntityManager. */
+export interface ShoppingListTransactionRepositories {
+    /** Lists, shares and defaults, on the transaction's manager. */
+    lists: ShoppingListRepository;