fix: update connection handling in ProxyHostForm and improve tooltip descriptions in useDocker

frontend/src/hooks/useDocker.ts

@@ -1,7 +1,7 @@
 import { useQuery } from '@tanstack/react-query'
 import { dockerApi } from '../api/docker'
 
-export function useDocker(host?: string) {
+export function useDocker(host?: string | null) {
   const {
     data: containers = [],
     isLoading,
@@ -9,7 +9,8 @@ export function useDocker(host?: string) {
     refetch,
   } = useQuery({
     queryKey: ['docker-containers', host],
-    queryFn: () => dockerApi.listContainers(host),
+    queryFn: () => dockerApi.listContainers(host || undefined),
+    enabled: host !== null, // Disable if host is explicitly null
     retry: 1, // Don't retry too much if docker is not available
   })