feat: private forum groups - Group/GroupMember models, group CRUD API, invite codes, private threads, groups UI pages

prisma/schema.prisma

@@ -35,6 +35,8 @@ model User {
   cashouts       CashoutRequest[]
   halalBookmarks HalalBookmark[]
   halalUsage     HalalUsage?
+  ownedGroups    Group[]           @relation("GroupOwner")
+  groupMemberships GroupMember[]
   forumThreads   ForumThread[]
   forumPosts     ForumPost[]
   chatHistory    ChatHistory[]
@@ -158,7 +160,34 @@ model ForumThread {
   shariahFlags  String?
   createdAt     DateTime       @default(now())
 
-  posts ForumPost[]
+  posts    ForumPost[]
+  group    Group?        @relation(fields: [groupId], references: [id])
+  groupId  String?
+}
+
+model Group {
+  id         String        @id @default(cuid())
+  name       String
+  description String?
+  ownerId    String
+  owner      User          @relation("GroupOwner", fields: [ownerId], references: [id])
+  inviteCode String        @unique
+  createdAt  DateTime      @default(now())
+
+  members    GroupMember[]
+  threads    ForumThread[]
+}
+
+model GroupMember {
+  id        String   @id @default(cuid())
+  groupId   String
+  group     Group    @relation(fields: [groupId], references: [id])
+  userId    String
+  user      User     @relation(fields: [userId], references: [id])
+  role      String   @default("member")
+  joinedAt  DateTime @default(now())
+
+  @@unique([groupId, userId])
 }
 
 model ForumPost {