M-029 Pass 1 batch 5: migrate 2 four-mutation pages to useTrackedMutation

Drains 8 more useMutation sites (18 -> 10). NetworkScanPage hoists the

shared invalidation array into scanTargetInvalidates const.

Pages migrated:

  - IssuersPage.tsx        test/delete/create/update all invalidate [['issuers']]

                            (testIssuerConnection updates last_tested_at

                             server-side, so the list refreshes; local

                             setTestResult banner still surfaces immediate result)

                            (queryClient + useQueryClient dropped)

  - NetworkScanPage.tsx    create/delete/toggle/scan all invalidate

                            [['network-scan-targets']] (hoisted to shared const)

                            (queryClient + useQueryClient dropped)

Verification:

  legacy useMutation count   18 -> 10 (-8)

  useTrackedMutation count   38 -> 46 (+8)

Closes 46 of 56 sites toward M-029 Pass 1 completion (82%).

web/src/pages/NetworkScanPage.tsx

@@ -1,5 +1,6 @@
 import { useState } from 'react';
-import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { useQuery } from '@tanstack/react-query';
+import { useTrackedMutation } from '../hooks/useTrackedMutation';
 import {
   getNetworkScanTargets,
   createNetworkScanTarget,
@@ -119,7 +120,6 @@ function CreateScanTargetModal({ onClose, onCreate }: {
 
 export default function NetworkScanPage() {
   const [showCreate, setShowCreate] = useState(false);
-  const queryClient = useQueryClient();
 
   const { data, isLoading, error, refetch } = useQuery({
     queryKey: ['network-scan-targets'],
@@ -127,28 +127,31 @@ export default function NetworkScanPage() {
     refetchInterval: 30000,
   });
 
-  const createMutation = useMutation({
+  // Every network-scan-target mutation invalidates the same list query.
+  const scanTargetInvalidates = [['network-scan-targets']];
+
+  const createMutation = useTrackedMutation({
     mutationFn: createNetworkScanTarget,
+    invalidates: scanTargetInvalidates,
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: ['network-scan-targets'] });
       setShowCreate(false);
     },
   });
 
-  const deleteMutation = useMutation({
+  const deleteMutation = useTrackedMutation({
     mutationFn: deleteNetworkScanTarget,
-    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['network-scan-targets'] }),
+    invalidates: scanTargetInvalidates,
   });
 
-  const toggleMutation = useMutation({
+  const toggleMutation = useTrackedMutation({
     mutationFn: ({ id, enabled }: { id: string; enabled: boolean }) =>
       updateNetworkScanTarget(id, { enabled }),
-    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['network-scan-targets'] }),
+    invalidates: scanTargetInvalidates,
   });
 
-  const scanMutation = useMutation({
+  const scanMutation = useTrackedMutation({
     mutationFn: triggerNetworkScan,
-    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['network-scan-targets'] }),
+    invalidates: scanTargetInvalidates,
   });
 
   const columns: Column<NetworkScanTarget>[] = [