fix(ui): only show indexing modal when indexing starts successfully

Move modal logic into else branch so it only triggers when indexResponse.ok.
Failed indexing still shows warning toast but no progress modal.

Author: DevanshuNEU

frontend/src/components/dashboard/DashboardHome.tsx

@@ -157,10 +157,8 @@ export function DashboardHome() {
           toast.warning(`${repo.name} added but indexing failed`, { 
             description: errMsg 
           })
-        }
-        
-        // Show progress for last repo
-        if (repo === githubRepos[githubRepos.length - 1]) {
+        } else if (repo === githubRepos[githubRepos.length - 1]) {
+          // Only show progress modal for last repo if indexing started successfully
           setIndexingRepoId(data.repo_id)
           setIndexingRepoName(repo.name)
           setShowIndexingModal(true)