feat: initialize Annual Gala Interactive System monorepo

- Set up pnpm workspace with 4 packages: shared, server, client-mobile, client-screen
- Implement Redis atomic voting with Lua scripts (HINCRBY + distributed lock)
- Add optimistic UI with IndexedDB queue for offline resilience
- Configure Socket.io with auto-reconnection (infinite retries)
- Separate mobile (Vant) and big screen (Pixi.js) dependencies

Tech stack:
- Frontend Mobile: Vue 3 + Vant + Socket.io-client
- Frontend Screen: Vue 3 + Pixi.js + GSAP
- Backend: Express + Socket.io + Redis + Prisma/MySQL

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

packages/server/prisma/schema.prisma

@@ -0,0 +1,115 @@
+generator client {
+  provider = "prisma-client-js"
+}
+
+datasource db {
+  provider = "mysql"
+  url      = env("DATABASE_URL")
+}
+
+// Users table
+model User {
+  id         String   @id @default(cuid())
+  name       String   @db.VarChar(100)
+  department String   @db.VarChar(100)
+  avatar     String?  @db.VarChar(512)
+  birthYear  Int?     @map("birth_year")
+  zodiac     String?  @db.VarChar(20)
+  isActive   Boolean  @default(true) @map("is_active")
+  createdAt  DateTime @default(now()) @map("created_at")
+  updatedAt  DateTime @updatedAt @map("updated_at")
+
+  votes       Vote[]
+  drawResults DrawResult[]
+
+  @@map("users")
+}
+
+// Candidates for voting
+model Candidate {
+  id          String   @id @default(cuid())
+  name        String   @db.VarChar(100)
+  department  String   @db.VarChar(100)
+  avatar      String?  @db.VarChar(512)
+  description String?  @db.Text
+  category    String   @db.VarChar(50)
+  isActive    Boolean  @default(true) @map("is_active")
+  createdAt   DateTime @default(now()) @map("created_at")
+
+  votes      Vote[]
+  voteCounts VoteCount[]
+
+  @@index([category])
+  @@map("candidates")
+}
+
+// Individual votes
+model Vote {
+  id          String   @id @default(cuid())
+  userId      String   @map("user_id")
+  candidateId String   @map("candidate_id")
+  category    String   @db.VarChar(50)
+  localId     String?  @map("local_id") @db.VarChar(64)
+  createdAt   DateTime @default(now()) @map("created_at")
+
+  user      User      @relation(fields: [userId], references: [id])
+  candidate Candidate @relation(fields: [candidateId], references: [id])
+
+  @@unique([userId, category])
+  @@index([category, candidateId])
+  @@index([createdAt])
+  @@map("votes")
+}
+
+// Aggregated vote counts (denormalized for performance)
+model VoteCount {
+  id          String   @id @default(cuid())
+  candidateId String   @map("candidate_id")
+  category    String   @db.VarChar(50)
+  count       Int      @default(0)
+  updatedAt   DateTime @updatedAt @map("updated_at")
+
+  candidate Candidate @relation(fields: [candidateId], references: [id])
+
+  @@unique([candidateId, category])
+  @@index([category, count(sort: Desc)])
+  @@map("vote_counts")
+}
+
+// Lucky draw results
+model DrawResult {
+  id               String   @id @default(cuid())
+  drawId           String   @map("draw_id")
+  prizeLevel       String   @map("prize_level") @db.VarChar(20)
+  prizeName        String   @map("prize_name") @db.VarChar(100)
+  winnerId         String   @map("winner_id")
+  winnerName       String   @map("winner_name") @db.VarChar(100)
+  winnerDepartment String   @map("winner_department") @db.VarChar(100)
+  drawnAt          DateTime @default(now()) @map("drawn_at")
+  drawnBy          String   @map("drawn_by") @db.VarChar(100)
+
+  winner User @relation(fields: [winnerId], references: [id])
+
+  @@index([drawId])
+  @@index([prizeLevel])
+  @@index([winnerId])
+  @@map("draw_results")
+}
+
+// Draw sessions
+model DrawSession {
+  id           String    @id @default(cuid())
+  prizeLevel   String    @map("prize_level") @db.VarChar(20)
+  prizeName    String    @map("prize_name") @db.VarChar(100)
+  totalPrizes  Int       @map("total_prizes")
+  drawnCount   Int       @default(0) @map("drawn_count")
+  isActive     Boolean   @default(false) @map("is_active")
+  filters      Json?
+  startedAt    DateTime? @map("started_at")
+  endedAt      DateTime? @map("ended_at")
+  createdAt    DateTime  @default(now()) @map("created_at")
+
+  @@index([prizeLevel])
+  @@index([isActive])
+  @@map("draw_sessions")
+}