feat(leader): Leader 管理展示跟单/回测数量并支持跳转筛选

- 后端：LeaderDto 增加 backtestCount，LeaderService 统计回测数并返回
- Leader 列表：展示跟单数、回测数，点击跳转跟单配置/回测页并带 leaderId 筛选
- 跟单配置页：从 URL 读取 leaderId 并应用筛选，Leader 下拉改用 LeaderSelect
- 回测页：支持 Leader 筛选，页面加载时请求 Leader 列表，筛选与详情统一显示规则
- LeaderSelect：支持 style，回测/跟单筛选统一使用
- 多语言：补充 leaderList 相关 key
- 移动端：Leader 管理卡片内按钮增加内边距 padding 8px 16px

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

frontend/src/locales/en/common.json

@@ -434,7 +434,10 @@
     "openWebsite": "Open Website",
     "all": "All",
     "copyTradingCount": "Copy Trading Count",
+    "backtestCount": "Backtest Count",
     "copyTradingRelations": "{{count}} copy trading relations",
+    "viewCopyTradings": "View Copy Tradings",
+    "viewBacktests": "View Backtests",
     "createdAt": "Created At",
     "noData": "No Leader data",
     "fetchFailed": "Failed to get Leader list",
@@ -442,7 +445,9 @@
     "deleteFailed": "Failed to delete Leader",
     "deleteConfirm": "Are you sure you want to delete this Leader?",
     "deleteConfirmDesc": "This Leader has {{count}} copy trading relations, please delete them first",
-    "openDetailFailed": "Failed to open detail"
+    "openDetailFailed": "Failed to open detail",
+    "noCopyTradings": "No copy trading configs",
+    "noBacktests": "No backtests"
   },
   "leaderAdd": {
     "title": "Add Leader",

frontend/src/locales/zh-CN/common.json

@@ -434,7 +434,10 @@
     "openWebsite": "打开网页",
     "all": "全部",
     "copyTradingCount": "跟单数",
+    "backtestCount": "回测数",
     "copyTradingRelations": "{{count}} 个跟单关系",
+    "viewCopyTradings": "查看跟单配置",
+    "viewBacktests": "查看回测",
     "createdAt": "创建时间",
     "noData": "暂无 Leader 数据",
     "fetchFailed": "获取 Leader 列表失败",
@@ -442,7 +445,9 @@
     "deleteFailed": "删除 Leader 失败",
     "deleteConfirm": "确定要删除这个 Leader 吗？",
     "deleteConfirmDesc": "该 Leader 还有 {{count}} 个跟单关系，请先删除跟单关系",
-    "openDetailFailed": "打开详情失败"
+    "openDetailFailed": "打开详情失败",
+    "noCopyTradings": "暂无跟单配置",
+    "noBacktests": "暂无回测"
   },
   "leaderAdd": {
     "title": "添加 Leader",

frontend/src/locales/zh-TW/common.json

@@ -434,7 +434,10 @@
     "openWebsite": "打開網頁",
     "all": "全部",
     "copyTradingCount": "跟單數",
+    "backtestCount": "回測數",
     "copyTradingRelations": "{{count}} 個跟單關係",
+    "viewCopyTradings": "查看跟單配置",
+    "viewBacktests": "查看回測",
     "createdAt": "創建時間",
     "noData": "暫無 Leader 數據",
     "fetchFailed": "獲取 Leader 列表失敗",
@@ -442,7 +445,9 @@
     "deleteFailed": "刪除 Leader 失敗",
     "deleteConfirm": "確定要刪除這個 Leader 嗎？",
     "deleteConfirmDesc": "該 Leader 還有 {{count}} 個跟單關係，請先刪除跟單關係",
-    "openDetailFailed": "打開詳情失敗"
+    "openDetailFailed": "打開詳情失敗",
+    "noCopyTradings": "暫無跟單配置",
+    "noBacktests": "暫無回測"
   },
   "leaderAdd": {
     "title": "添加 Leader",