Frontend: use github-versions.json for version display (#11281)

* fix(frontend): use github-versions.json for version display

- Update AppVersion type to match new format with slug field
- Switch from versions.json to github-versions.json API
- Simplify version matching by direct slug comparison
- Remove 'Loading versions...' text - show nothing if no version found

* feat(frontend): show tooltip for pinned versions

* fix(api): add github-versions endpoint and fix legacy versions route

frontend/src/hooks/use-versions.ts

@@ -2,7 +2,7 @@
 
 import { useQuery } from "@tanstack/react-query";
 
-import type { AppVersion } from "@/lib/types";
+import type { AppVersion, GitHubVersionsResponse } from "@/lib/types";
 
 import { fetchVersions } from "@/lib/data";
 
@@ -10,14 +10,8 @@ export function useVersions() {
   return useQuery<AppVersion[]>({
     queryKey: ["versions"],
     queryFn: async () => {
-      const fetchedVersions = await fetchVersions();
-      if (Array.isArray(fetchedVersions)) {
-        return fetchedVersions;
-      }
-      if (fetchedVersions && typeof fetchedVersions === "object") {
-        return [fetchedVersions];
-      }
-      return [];
+      const response: GitHubVersionsResponse = await fetchVersions();
+      return response.versions ?? [];
     },
   });
 }