feat: initial elysium idle game prototype

Sets up the full monorepo with pnpm workspaces. Includes shared types
package, Hono API with Discord OAuth/JWT auth, Prisma v6 + MongoDB
Atlas, and React + Vite frontend with game loop, five tabs, and
Discord-linked save/load.

apps/api/prisma/schema.prisma

@@ -0,0 +1,38 @@
+generator client {
+  provider = "prisma-client-js"
+}
+
+datasource db {
+  provider = "mongodb"
+  url      = env("DATABASE_URL")
+}
+
+model Player {
+  id              String  @id @default(auto()) @map("_id") @db.ObjectId
+  discordId       String  @unique
+  username        String
+  discriminator   String
+  avatar          String?
+  characterName   String  @default("")
+  createdAt       Float
+  lastSavedAt     Float
+  totalGoldEarned Float   @default(0)
+  totalClicks     Float   @default(0)
+}
+
+model GameState {
+  id        String @id @default(auto()) @map("_id") @db.ObjectId
+  discordId String @unique
+  state     Json
+  updatedAt Float
+}
+
+model BossDamageLog {
+  id        String @id @default(auto()) @map("_id") @db.ObjectId
+  discordId String
+  bossId    String
+  damage    Float
+  dealtAt   Float
+
+  @@index([discordId, bossId, dealtAt])
+}