Bulk Dell warranty sync + add-warranty from asset pages

- POST /warranty/sync/dell: auto-detect Dell hardware by service tag (asset
  serial) and create warranties for the ones Dell recognizes, in batches of 100.
  Only looks up assets that lack a dated warranty, so re-runs are cheap and
  non-Dell serials are filtered out by Dell. DellProvider.bulk_lookup batches
  tags over the cached token.
- "Sync Dell" button on the Warranties page with a toast summary.
- WarrantyPanel "Add one / Add-manage" links deep-link to the warranties add
  modal pre-linked to that asset (?addfor=); WarrantiesList opens it prefilled.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/src/api/index.js

@@ -970,6 +970,9 @@ export const warrantyApi = {
   refresh(id) {
     return api.post(`/warranty/${id}/refresh`)
   },
+  syncDell() {
+    return api.post('/warranty/sync/dell')
+  },
   report() {
     return api.get('/warranty/report')
   }

frontend/src/components/WarrantyPanel.vue

@@ -14,12 +14,12 @@
           <span v-if="w.servicetag" class="mono">Tag {{ w.servicetag }}</span>
         </div>
       </div>
-      <router-link to="/warranties" class="warranty-manage">Manage warranties</router-link>
+      <router-link :to="`/warranties?addfor=${assetid}`" class="warranty-manage">Add / manage</router-link>
     </div>
 
     <div v-else class="warranty-empty">
       <span class="muted">No warranty on record.</span>
-      <router-link to="/warranties" class="warranty-manage">Add one</router-link>
+      <router-link :to="`/warranties?addfor=${assetid}`" class="warranty-manage">Add one</router-link>
     </div>
   </div>
 </template>

frontend/src/views/warranty/WarrantiesList.vue

@@ -2,7 +2,12 @@
   <div>
     <div class="page-header">
       <h2>Warranties</h2>
-      <button class="btn btn-primary" @click="openModal()">+ Add Warranty</button>
+      <div class="header-actions">
+        <button class="btn btn-secondary" :disabled="syncing" @click="syncDell">
+          {{ syncing ? 'Syncing Dell...' : 'Sync Dell' }}
+        </button>
+        <button class="btn btn-primary" @click="openModal()">+ Add Warranty</button>
+      </div>
     </div>
 
 
@@ -137,14 +142,17 @@
 
 <script setup>
 import { ref, onMounted } from 'vue'
+import { useRoute } from 'vue-router'
 import { colorStyle } from '@/utils/colorStyle'
 import { warrantyApi, assetsApi } from '../../api'
 import { useToast } from '../../composables/toast'
 
 const toast = useToast()
+const route = useRoute()
 
 const items = ref([])
 const loading = ref(true)
+const syncing = ref(false)
 const statusFilter = ref('')
 const showModal = ref(false)
 const editing = ref(null)
@@ -171,7 +179,21 @@ function assetLink(a) {
   return base + a.assetid
 }
 
-onMounted(loadData)
+onMounted(async () => {
+  await loadData()
+  // Deep-link from an asset detail page: open the add modal pre-linked to it.
+  const addfor = route.query.addfor
+  if (addfor) {
+    openModal()
+    try {
+      const response = await assetsApi.get(addfor)
+      const asset = response.data.data
+      if (asset) selectedAssets.value = [{ assetid: asset.assetid, assetnumber: asset.assetnumber }]
+    } catch (err) {
+      selectedAssets.value = [{ assetid: Number(addfor), assetnumber: `Asset ${addfor}` }]
+    }
+  }
+})
 
 async function loadData() {
   loading.value = true
@@ -269,6 +291,21 @@ async function deleteWarranty(w) {
   }
 }
 
+async function syncDell() {
+  syncing.value = true
+  toast.info('Looking up Dell service tags... this can take a moment.')
+  try {
+    const response = await warrantyApi.syncDell()
+    const summary = response.data?.data || {}
+    loadData()
+    toast.success(`Dell sync: ${summary.created || 0} added, ${summary.updated || 0} updated (${summary.matched || 0} tags matched).`)
+  } catch (err) {
+    toast.error(apiError(err, 'Dell sync failed'))
+  } finally {
+    syncing.value = false
+  }
+}
+
 async function refresh(w) {
   try {
     const response = await warrantyApi.refresh(w.warrantyid)