feat: add Admin Control Panel, voting status check, and router security

Admin Control Panel:
- Add full AdminControl.vue with 3 sections (Voting, Lottery, Global)
- Add AdminLogin.vue with access code gate (20268888)
- Add admin.ts store with state persistence
- Add admin.types.ts with state machine types
- Add router guards for /admin/director-console

Voting System Fixes:
- Add voting status check before accepting votes (VOTING_CLOSED error)
- Fix client to display server error messages
- Fix button disabled logic to prevent ambiguity in paused state
- Auto-generate userId on connect to fix UNAUTHORIZED error

Big Screen Enhancements:
- Add LiveVotingView.vue with particle system
- Add LotteryMachine.ts with 3-stage animation (Galaxy/Storm/Reveal)
- Add useSocketClient.ts composable
- Fix MainDisplay.vue SCSS syntax error
- Add admin state sync listener in display store

Server Updates:
- Add admin.service.ts for state management
- Add isVotingOpen() and getVotingStatus() methods
- Add admin socket event handlers

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

packages/client-screen/src/views/AdminLogin.vue

@@ -0,0 +1,181 @@
+<script setup lang="ts">
+import { ref } from 'vue';
+import { useRouter, useRoute } from 'vue-router';
+import { ADMIN_TOKEN_KEY, ADMIN_ACCESS_CODE, generateToken } from '../router';
+
+const router = useRouter();
+const route = useRoute();
+
+const accessCode = ref('');
+const error = ref('');
+const isLoading = ref(false);
+
+async function handleLogin() {
+  error.value = '';
+
+  if (!accessCode.value.trim()) {
+    error.value = '请输入访问码';
+    return;
+  }
+
+  isLoading.value = true;
+
+  // Simulate network delay for UX
+  await new Promise(resolve => setTimeout(resolve, 500));
+
+  if (accessCode.value === ADMIN_ACCESS_CODE) {
+    // Save token to localStorage
+    localStorage.setItem(ADMIN_TOKEN_KEY, generateToken(ADMIN_ACCESS_CODE));
+
+    // Redirect to console or original destination
+    const redirect = route.query.redirect as string || '/admin/director-console';
+    router.push(redirect);
+  } else {
+    error.value = '访问码错误';
+    accessCode.value = '';
+  }
+
+  isLoading.value = false;
+}
+
+function handleKeydown(e: KeyboardEvent) {
+  if (e.key === 'Enter') {
+    handleLogin();
+  }
+}
+</script>
+
+<template>
+  <div class="admin-login">
+    <div class="login-box">
+      <div class="lock-icon">🔒</div>
+      <h1 class="title">导演控制台</h1>
+      <p class="subtitle">请输入访问码</p>
+
+      <div class="input-group">
+        <input
+          v-model="accessCode"
+          type="password"
+          placeholder="访问码"
+          autocomplete="off"
+          :disabled="isLoading"
+          @keydown="handleKeydown"
+        />
+      </div>
+
+      <div v-if="error" class="error-message">
+        {{ error }}
+      </div>
+
+      <button
+        class="login-btn"
+        :disabled="isLoading"
+        @click="handleLogin"
+      >
+        {{ isLoading ? '验证中...' : '进入控制台' }}
+      </button>
+
+      <p class="hint">仅限活动导演使用</p>
+    </div>
+  </div>
+</template>
+
+<style lang="scss" scoped>
+.admin-login {
+  width: 100%;
+  height: 100%;
+  background: #0a0a0a;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+}
+
+.login-box {
+  width: 360px;
+  padding: 40px;
+  text-align: center;
+}
+
+.lock-icon {
+  font-size: 48px;
+  margin-bottom: 20px;
+  opacity: 0.6;
+}
+
+.title {
+  font-size: 24px;
+  font-weight: 600;
+  color: #e0e0e0;
+  margin: 0 0 8px 0;
+}
+
+.subtitle {
+  font-size: 14px;
+  color: #666;
+  margin: 0 0 32px 0;
+}
+
+.input-group {
+  margin-bottom: 16px;
+
+  input {
+    width: 100%;
+    padding: 14px 16px;
+    font-size: 16px;
+    background: #1a1a1a;
+    border: 1px solid #333;
+    border-radius: 8px;
+    color: #e0e0e0;
+    text-align: center;
+    letter-spacing: 4px;
+
+    &:focus {
+      outline: none;
+      border-color: #3b82f6;
+    }
+
+    &:disabled {
+      opacity: 0.5;
+    }
+
+    &::placeholder {
+      letter-spacing: normal;
+      color: #555;
+    }
+  }
+}
+
+.error-message {
+  color: #ef4444;
+  font-size: 14px;
+  margin-bottom: 16px;
+}
+
+.login-btn {
+  width: 100%;
+  padding: 14px;
+  font-size: 16px;
+  font-weight: 500;
+  background: #3b82f6;
+  border: none;
+  border-radius: 8px;
+  color: white;
+  cursor: pointer;
+  transition: background 0.2s;
+
+  &:hover:not(:disabled) {
+    background: #2563eb;
+  }
+
+  &:disabled {
+    opacity: 0.6;
+    cursor: not-allowed;
+  }
+}
+
+.hint {
+  font-size: 12px;
+  color: #444;
+  margin: 24px 0 0 0;
+}
+</style>