feat: implement user-scoped receipt aliases with global fallback; enhance alias management in admin panel

backend/prisma/migrations/20260504130000_receipt_alias_user_scope/migration.sql

@@ -0,0 +1,25 @@
+-- Make receipt aliases user-scoped with optional admin-managed global fallback.
+ALTER TABLE `ReceiptAlias`
+  ADD COLUMN `ownerId` INT NULL,
+  ADD COLUMN `isGlobal` BOOLEAN NOT NULL DEFAULT false;
+
+-- Existing aliases become global aliases.
+UPDATE `ReceiptAlias`
+SET `isGlobal` = true
+WHERE `isGlobal` = false;
+
+-- Replace previous global unique key on receiptName.
+ALTER TABLE `ReceiptAlias`
+  DROP INDEX `ReceiptAlias_receiptName_key`;
+
+-- Add scoped uniqueness and lookup indexes.
+ALTER TABLE `ReceiptAlias`
+  ADD UNIQUE INDEX `ReceiptAlias_receiptName_ownerId_isGlobal_key`(`receiptName`, `ownerId`, `isGlobal`),
+  ADD INDEX `ReceiptAlias_ownerId_idx`(`ownerId`),
+  ADD INDEX `ReceiptAlias_isGlobal_idx`(`isGlobal`);
+
+-- Link aliases to owner when user-scoped.
+ALTER TABLE `ReceiptAlias`
+  ADD CONSTRAINT `ReceiptAlias_ownerId_fkey`
+  FOREIGN KEY (`ownerId`) REFERENCES `User`(`id`)
+  ON DELETE CASCADE ON UPDATE CASCADE;

backend/prisma/schema.prisma

@@ -26,6 +26,7 @@ model User {
   ownedProducts Product[]
   pantryItems PantryItem[]
   mealPlanEntries MealPlanEntry[]
+  receiptAliases  ReceiptAlias[]
 }
 
 model Product {
@@ -175,10 +176,17 @@ model PantryItem {
 
 model ReceiptAlias {
   id           Int      @id @default(autoincrement())
-  receiptName  String   @unique  // normaliserat kvittonamn (lowercase, trim)
+  receiptName  String   // normaliserat kvittonamn (lowercase, trim)
+  ownerId      Int?
+  owner        User?    @relation(fields: [ownerId], references: [id], onDelete: Cascade)
+  isGlobal     Boolean  @default(false)
   productId    Int
   product      Product  @relation(fields: [productId], references: [id], onDelete: Cascade)
   createdAt    DateTime @default(now())
+
+  @@unique([receiptName, ownerId, isGlobal])
+  @@index([ownerId])
+  @@index([isGlobal])
 }
 
 model MealPlanEntry {