Standardise frontend hook fetch error handling and mark Task 12 done

frontend/src/hooks/useSetup.ts

@@ -6,6 +6,7 @@
 
 import { useCallback, useEffect, useState } from "react";
 import { ApiError } from "../api/client";
+import { handleFetchError } from "../utils/fetchError";
 import { getSetupStatus, submitSetup } from "../api/setup";
 import type {
   SetupRequest,
@@ -44,9 +45,11 @@ export function useSetup(): UseSetupResult {
       const resp = await getSetupStatus();
       setStatus(resp);
     } catch (err: unknown) {
-      const errorMessage = err instanceof Error ? err.message : "Failed to fetch setup status";
-      console.warn("Setup status check failed:", errorMessage);
-      setError(errorMessage);
+      const fallback = "Failed to fetch setup status";
+      handleFetchError(err, setError, fallback);
+      if (!(err instanceof DOMException && err.name === "AbortError")) {
+        console.warn("Setup status check failed:", err instanceof Error ? err.message : fallback);
+      }
     } finally {
       setLoading(false);
     }