pw change, leaderboard, lotto, related ht, admin ban, add, and display changes

prisma/schema.prisma

@@ -8,14 +8,16 @@ datasource db {
 }
 
 model User {
-  id             String          @id @default(cuid())
-  username       String          @unique
-  passwordHash   String
-  balance        Float           @default(2000)
-  researchPoints Int             @default(1)
-  isAdmin        Boolean         @default(false)
-  createdAt      DateTime        @default(now())
-  updatedAt      DateTime        @updatedAt
+  id              String          @id @default(cuid())
+  username        String          @unique  // lowercase, used for URLs/lookups
+  displayUsername String?                  // original casing chosen by user
+  passwordHash    String
+  balance         Float           @default(2000)
+  researchPoints  Int             @default(1)
+  isAdmin         Boolean         @default(false)
+  lastLotteryAt   DateTime?       // tracks daily lottery cooldown
+  createdAt       DateTime        @default(now())
+  updatedAt       DateTime        @updatedAt
 
   positions      Position[]
   trades         Trade[]
@@ -40,18 +42,35 @@ model Hashtag {
   displayTag   String         // original case as entered
   currentPrice Float          @default(0.25)
   isActive     Boolean        @default(true)
+  isBanned     Boolean        @default(false)
   // Consecutive zero-result count; after 3 failed updates the hashtag auto-deactivates
   zeroCount    Int            @default(0)
   lastUpdated  DateTime       @default(now())
   createdAt    DateTime       @default(now())
 
-  priceHistory PriceHistory[]
-  positions    Position[]
-  trades       Trade[]
+  priceHistory    PriceHistory[]
+  positions       Position[]
+  trades          Trade[]
+  relatedFrom     RelatedHashtag[] @relation("RelatedFrom")
+  relatedTo       RelatedHashtag[] @relation("RelatedTo")
 
   @@index([isActive, lastUpdated])
 }
 
+model RelatedHashtag {
+  id           String  @id @default(cuid())
+  hashtagId    String
+  hashtag      Hashtag @relation("RelatedFrom", fields: [hashtagId], references: [id], onDelete: Cascade)
+  relatedTag   String  // lowercase tag name (may not yet be in Hashtag table)
+  relatedId    String? // set if the related hashtag exists in the DB
+  related      Hashtag? @relation("RelatedTo", fields: [relatedId], references: [id], onDelete: SetNull)
+  coOccurrences Int    @default(1)
+  updatedAt    DateTime @updatedAt
+
+  @@unique([hashtagId, relatedTag])
+  @@index([hashtagId, coOccurrences])
+}
+
 model PriceHistory {
   id           String   @id @default(cuid())
   hashtagId    String