feat(api): add MS21 user fields for admin, local auth, and invitations

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/api/prisma/schema.prisma

@@ -227,6 +227,14 @@ model User {
   createdAt      DateTime @default(now()) @map("created_at") @db.Timestamptz
   updatedAt      DateTime @updatedAt @map("updated_at") @db.Timestamptz
 
+  // MS21: Admin, local auth, and invitation fields
+  deactivatedAt   DateTime?  @map("deactivated_at") @db.Timestamptz
+  isLocalAuth     Boolean    @default(false) @map("is_local_auth")
+  passwordHash    String?    @map("password_hash")
+  invitedBy       String?    @map("invited_by") @db.Uuid
+  invitationToken String?    @unique @map("invitation_token")
+  invitedAt       DateTime?  @map("invited_at") @db.Timestamptz
+
   // Relations
   ownedWorkspaces        Workspace[]             @relation("WorkspaceOwner")
   workspaceMemberships   WorkspaceMember[]