Add new API endpoint for retrieving submissions by challenge chain; update frontend to support chain selection and display participant progress. Enhance localization for submissions page in English and Russian.

src/__data__/urls.ts

@@ -36,8 +36,10 @@ export const URLs = {
   
   // Submissions
   submissions: makeUrl('/submissions'),
-  submissionDetails: (userId: string, submissionId: string) => makeUrl(`/submissions/${userId}/${submissionId}`),
-  submissionDetailsPath: makeUrl('/submissions/:userId/:submissionId'),
+  submissionsChain: (chainId: string) => makeUrl(`/submissions/${chainId}`),
+  submissionsChainPath: makeUrl('/submissions/:chainId'),
+  submissionDetails: (chainId: string, userId: string, submissionId: string) => makeUrl(`/submissions/${chainId}/${userId}/${submissionId}`),
+  submissionDetailsPath: makeUrl('/submissions/:chainId/:userId/:submissionId'),
   
   // External links
   challengePlayer: navs['link.challenge.main'] || '/challenge',