Fix promise cancellation in 5 components with AbortController refs

Add AbortController refs and abort signal checks to prevent race conditions
and memory leaks when components unmount or new requests are initiated.

Components fixed:
- JailsTab.tsx: validation handler with AbortController pattern
- JailInfoSection.tsx: handle function with useCallback wrapper
- RawConfigSection.tsx: fetch handler with abort checks
- ConfFilesTab.tsx: file fetch handler with abort signal verification
- IgnoreListSection.tsx: three handlers (add, remove, toggle) with callbacks

All handlers now:
1. Abort previous requests before initiating new ones
2. Create and store new AbortController instances
3. Check abort status before state updates in .then()/.catch()
4. Include cleanup effects that abort on unmount

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

frontend/src/components/config/JailsTab.tsx

@@ -725,19 +725,37 @@ function InactiveJailDetail({
   const [validating, setValidating] = useState(false);
   const [validationResult, setValidationResult] = useState<JailValidationResult | null>(null);
   const [validationError, setValidationError] = useState<string | null>(null);
+  const validateControllerRef = useRef<AbortController | null>(null);
 
   const handleValidate = useCallback((): void => {
+    validateControllerRef.current?.abort();
+    const controller = new AbortController();
+    validateControllerRef.current = controller;
+
     setValidating(true);
     setValidationResult(null);
     setValidationError(null);
     onValidate()
-      .then((result) => { setValidationResult(result); })
+      .then((result) => {
+        if (controller.signal.aborted) return;
+        setValidationResult(result);
+      })
       .catch((err: unknown) => {
+        if (controller.signal.aborted) return;
         handleFetchError(err, createStringErrorAdapter(setValidationError), "Validation request failed.");
       })
-      .finally(() => { setValidating(false); });
+      .finally(() => {
+        if (controller.signal.aborted) return;
+        setValidating(false);
+      });
   }, [onValidate]);
 
+  useEffect(() => {
+    return (): void => {
+      validateControllerRef.current?.abort();
+    };
+  }, []);
+
   const blockingIssues: JailValidationIssue[] =
     validationResult?.issues.filter((i) => i.field !== "logpath") ?? [];
   const advisoryIssues: JailValidationIssue[] =