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/views/LoginView.vue

@@ -1,6 +1,6 @@
 <script setup lang="ts">
 import { ref } from 'vue';
-import { useRouter } from 'vue-router';
+import { useRouter, useRoute } from 'vue-router';
 import { useI18n } from 'vue-i18n';
 import { useAuthStore } from '../stores/auth';
 import { useAppLocale } from '../composables/useAppLocale';
@@ -12,6 +12,7 @@ const { t } = useI18n();
 const { initFromUser } = useAppLocale();
 const auth = useAuthStore();
 const router = useRouter();
+const route = useRoute();
 const captchaRef = ref<InstanceType<typeof RobotVerify> | null>(null);
 const username = ref('');
 const password = ref('');
@@ -29,13 +30,19 @@ async function submit() {
   try {
     await auth.login(username.value, password.value);
     initFromUser(auth.user?.locale);
-    router.push('/');
+    const redirectTo = (route.query.redirect as string) || '/';
+    router.push(redirectTo);
   } catch (e: unknown) {
     error.value = (e as { response?: { data?: { error?: string } } })?.response?.data?.error || 'Login failed';
   } finally {
     loading.value = false;
   }
 }
+
+function continueBrowsing() {
+  const redirect = (route.query.redirect as string) || '/';
+  router.push(redirect);
+}
 </script>
 
 <template>
@@ -53,6 +60,9 @@ async function submit() {
       <button type="submit" class="btn-login btn-gold-outline" :disabled="loading">
         {{ t('auth.login') }}
       </button>
+      <button type="button" class="btn-skip" @click="continueBrowsing">
+        {{ t('auth.continue_browsing') }}
+      </button>
     </form>
   </div>
 </template>
@@ -111,6 +121,21 @@ label {
   cursor: not-allowed;
 }
 
+.btn-skip {
+  margin-top: 2px;
+  padding: 8px 14px;
+  border: none;
+  background: transparent;
+  color: rgba(255, 255, 255, 0.55);
+  font-size: 13px;
+  font-weight: 600;
+  cursor: pointer;
+}
+
+.btn-skip:active {
+  color: rgba(255, 255, 255, 0.75);
+}
+
 .error {
   color: var(--danger);
   font-size: 13px;