feat: 前台匿名浏览、登录引导、客服入口与返水增强

前台：
- 未登录可浏览首页/赛事/赔率，下注等操作弹出登录引导（去登录/继续浏览）
- 顶部新增客服入口与 iframe 弹窗
- 登录页支持暂不登录返回浏览

API：
- 首页/赛事/冠军盘接口改为公开访问，支持 X-Locale 头
- JWT 守卫支持可选认证

返水：
- 注单新增 is_cashbacked 字段，发放时自动标记
- 预览展示玩家余额，明确平台直发不从代理扣款
- 后台注单列表与玩家历史展示回水状态

其他：
- 串关禁止同场重复选号（SAME_MATCH）
- 补充结算资金流分析文档

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/player/src/components/LoginPromptModal.vue

@@ -0,0 +1,154 @@
+<script setup lang="ts">
+import { useRouter } from 'vue-router';
+import { useI18n } from 'vue-i18n';
+import { useAuthStore } from '../stores/auth';
+
+const { t } = useI18n();
+const auth = useAuthStore();
+const router = useRouter();
+
+function goLogin() {
+  const redirect = auth.loginReturnTo || undefined;
+  auth.hideLoginPrompt();
+  router.push({
+    path: '/login',
+    query: redirect ? { redirect } : {},
+  });
+}
+
+function continueBrowsing() {
+  auth.loginReturnTo = '';
+  auth.hideLoginPrompt();
+}
+</script>
+
+<template>
+  <Teleport to="body">
+    <Transition name="fade">
+      <div v-if="auth.loginPromptVisible" class="login-overlay" @click.self="continueBrowsing">
+        <div class="login-modal">
+          <button type="button" class="close-btn" :aria-label="t('auth.continue_browsing')" @click="continueBrowsing">
+            ✕
+          </button>
+          <h2 class="login-title">{{ t('auth.login_required') }}</h2>
+          <p class="login-hint">{{ t('auth.login_hint') }}</p>
+
+          <div class="login-actions">
+            <button type="button" class="login-submit" @click="goLogin">
+              {{ t('auth.go_login') }}
+            </button>
+            <button type="button" class="login-secondary" @click="continueBrowsing">
+              {{ t('auth.continue_browsing') }}
+            </button>
+          </div>
+        </div>
+      </div>
+    </Transition>
+  </Teleport>
+</template>
+
+<style scoped>
+.login-overlay {
+  position: fixed;
+  inset: 0;
+  z-index: 999;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  background: rgba(0, 0, 0, 0.7);
+  backdrop-filter: blur(4px);
+  -webkit-backdrop-filter: blur(4px);
+}
+
+.login-modal {
+  position: relative;
+  width: 90%;
+  max-width: 360px;
+  background: #1a1a1a;
+  border: 1px solid var(--border-gold-soft, rgba(200, 168, 78, 0.25));
+  border-radius: 12px;
+  padding: 28px 24px 24px;
+}
+
+.close-btn {
+  position: absolute;
+  top: 12px;
+  right: 14px;
+  background: none;
+  border: none;
+  color: #666;
+  font-size: 18px;
+  cursor: pointer;
+  padding: 4px;
+  line-height: 1;
+}
+
+.close-btn:hover {
+  color: #aaa;
+}
+
+.login-title {
+  font-size: 18px;
+  font-weight: 800;
+  color: var(--primary-light, #c8a84e);
+  margin: 0 0 6px;
+  text-align: center;
+}
+
+.login-hint {
+  font-size: 12px;
+  color: #888;
+  text-align: center;
+  margin: 0 0 24px;
+}
+
+.login-actions {
+  display: flex;
+  flex-direction: column;
+  gap: 10px;
+}
+
+.login-submit {
+  padding: 12px;
+  border-radius: 8px;
+  border: none;
+  background: linear-gradient(135deg, #d4a017, #e8c84a);
+  color: #1a1a1a;
+  font-size: 15px;
+  font-weight: 800;
+  cursor: pointer;
+  min-height: 44px;
+  transition: opacity 0.2s;
+}
+
+.login-submit:active {
+  opacity: 0.85;
+}
+
+.login-secondary {
+  padding: 10px;
+  border-radius: 8px;
+  border: 1px solid #333;
+  background: transparent;
+  color: #888;
+  font-size: 14px;
+  font-weight: 600;
+  cursor: pointer;
+  min-height: 40px;
+  transition: color 0.2s, border-color 0.2s;
+}
+
+.login-secondary:active {
+  color: #aaa;
+  border-color: #444;
+}
+
+.fade-enter-active,
+.fade-leave-active {
+  transition: opacity 0.25s ease;
+}
+.fade-enter-from,
+.fade-leave-to {
+  opacity: 0;
+}
+</style>