refactor: remove username from User model, login by email only

prisma/schema.prisma

@@ -23,7 +23,6 @@ enum UserRole {
 
 model User {
   id          String       @id @default(uuid())
-  username    String       @unique
   name        String
   email       String       @unique
   password    String
@@ -133,8 +132,8 @@ model Assignment {
   item           Item?      @relation(fields: [itemId], references: [id], onDelete: SetNull, onUpdate: Cascade)
   assetId        String?    @unique
   asset          Asset?     @relation(fields: [assetId], references: [id], onDelete: SetNull, onUpdate: Cascade)
-  personId        String?
-  person          Person?    @relation(fields: [personId], references: [id], onDelete: Cascade, onUpdate: Cascade)
+  personId       String?
+  person         Person?    @relation(fields: [personId], references: [id], onDelete: Cascade, onUpdate: Cascade)
   assignmentDate DateTime   @default(now())
   returnDate     DateTime?
   createdBy      String
@@ -170,8 +169,8 @@ model Movement {
   asset         Asset?       @relation(fields: [assetId], references: [id], onDelete: SetNull, onUpdate: Cascade)
   previousStock Int?
   newStock      Int?
-  personId       String?
-  person         Person?      @relation(fields: [personId], references: [id], onDelete: SetNull, onUpdate: Cascade)
+  personId      String?
+  person        Person?      @relation(fields: [personId], references: [id], onDelete: SetNull, onUpdate: Cascade)
   assignmentId  String?
   assignment    Assignment?  @relation(fields: [assignmentId], references: [id], onDelete: SetNull, onUpdate: Cascade)
   userId        String
@@ -183,4 +182,4 @@ model Movement {
   @@index([personId])
   @@index([type])
   @@index([userId])
-}
+}