Add user filtering and progress overview to submissions page; enhance localization for user selection and progress display

stubs/api/data/stats-v2.json

@@ -200,6 +200,28 @@
     }
   ],
   "activeParticipants": [
+    {
+      "userId": "6909b51512c75d75a36a52bf",
+      "nickname": "Примаков А.А.",
+      "totalSubmissions": 14,
+      "completedTasks": 1,
+      "chainProgress": [
+          {
+              "chainId": "6909ad8612c75d75a36a4c58",
+              "chainName": "Это тестовая цепочка заданий",
+              "totalTasks": 2,
+              "completedTasks": 1,
+              "progressPercent": 50
+          },
+          {
+              "chainId": "690a30b1e723507972c44098",
+              "chainName": "Навыки работы с нейросетями для начинающих (пошагово)",
+              "totalTasks": 20,
+              "completedTasks": 1,
+              "progressPercent": 5
+          }
+      ]
+  },
     {
       "userId": "user_1",
       "nickname": "alex_dev",

stubs/api/index.js

@@ -61,6 +61,32 @@ const getStatsV2 = () => {
   return statsV2Cache;
 };
 
+// Enrich SystemStatsV2 with real user ids/nicknames from users.json
+const getStatsV2WithUsers = () => {
+  const statsV2 = getStatsV2();
+  const users = getUsers();
+
+  const mapParticipant = (participant, index) => {
+    const user = users[index];
+    if (!user) return participant;
+
+    return {
+      ...participant,
+      userId: user.id,
+      nickname: user.nickname,
+    };
+  };
+
+  return {
+    ...statsV2,
+    activeParticipants: statsV2.activeParticipants.map(mapParticipant),
+    chainsDetailed: statsV2.chainsDetailed.map((chain) => ({
+      ...chain,
+      participantProgress: chain.participantProgress.map(mapParticipant),
+    })),
+  };
+};
+
 router.use(timer());
 
 // ============= TASKS =============
@@ -282,7 +308,7 @@ router.get('/challenge/stats', (req, res) => {
 
 // GET /api/challenge/stats/v2
 router.get('/challenge/stats/v2', (req, res) => {
-  const statsV2 = getStatsV2();
+  const statsV2 = getStatsV2WithUsers();
   const chainId = req.query.chainId;
   
   // Если chainId не передан, возвращаем все данные