Added ability to control registration by admin user.

backend/prisma/schema.prisma

@@ -15,6 +15,8 @@ model User {
   screenName      String?
   avatarUrl       String?
   unitPreference  UnitPreference @default(METRIC)
+  isAdmin         Boolean       @default(false)
+  isApiEnabled    Boolean       @default(false)
   createdAt       DateTime      @default(now())
   updatedAt       DateTime      @updatedAt
   games           Game[]        @relation("GameMaster")
@@ -22,6 +24,7 @@ model User {
   captainOf       Team?         @relation("TeamCaptain")
   chatMessages    ChatMessage[]
   locationHistory LocationHistory[]
+  apiKeys         ApiKey[]
 }
 
 enum UnitPreference {
@@ -158,6 +161,32 @@ model LocationHistory {
   recordedAt DateTime @default(now())
 }
 
+model SystemSettings {
+  id                    String   @id @default("default")
+  registrationEnabled   Boolean  @default(true)
+  inviteCode            String?  @unique
+  updatedAt             DateTime @updatedAt
+}
+
+model BannedEmail {
+  id        String   @id @default(uuid())
+  email     String   @unique
+  reason    String?
+  createdAt DateTime @default(now())
+  updatedAt DateTime @updatedAt
+}
+
+model ApiKey {
+  id        String   @id @default(uuid())
+  key       String   @unique
+  name      String
+  userId    String
+  user      User     @relation(fields: [userId], references: [id], onDelete: Cascade)
+  expiresAt DateTime?
+  lastUsed  DateTime?
+  createdAt DateTime @default(now())
+}
+
 enum Visibility {
   PUBLIC
   PRIVATE