feat(assets): filter inventory by sync source

Dropdown on the Assets page (All / Wazuh / Nessus / Intune+Defender /
Manual). Backend already accepts ?source=; this just wires the UI.

frontend/app/assets/page.tsx

@@ -17,6 +17,7 @@ export default function AssetsPage() {
     const [isModalOpen, setIsModalOpen] = useState(false);
     const [searchText, setSearchText] = useState('');
     const [showInactive, setShowInactive] = useState(false);
+    const [sourceFilter, setSourceFilter] = useState('');
     // Table sort state
     const [sortBy, setSortBy] = useState<string>('hostname');
     const [sortOrder, setSortOrder] = useState<'asc' | 'desc'>('asc');
@@ -56,6 +57,7 @@ export default function AssetsPage() {
             const params: any = {};
             if (searchText) params.search = searchText;
             if (showInactive) params.include_inactive = true;
+            if (sourceFilter) params.source = sourceFilter;
             params.sort_by = sortBy;
             params.sort_order = sortOrder;
             params.limit = pageSize;
@@ -114,14 +116,14 @@ export default function AssetsPage() {
     useEffect(() => {
         setPage(1);
         // eslint-disable-next-line react-hooks/exhaustive-deps
-    }, [searchText, showInactive, sortBy, sortOrder, pageSize]);
+    }, [searchText, showInactive, sortBy, sortOrder, pageSize, sourceFilter]);
 
     // Fetch on page / filter / search change (debounced for typing).
     useEffect(() => {
         const t = setTimeout(fetchAssets, searchText ? 300 : 0);
         return () => clearTimeout(t);
         // eslint-disable-next-line react-hooks/exhaustive-deps
-    }, [page, pageSize, sortBy, sortOrder, showInactive, searchText]);
+    }, [page, pageSize, sortBy, sortOrder, showInactive, searchText, sourceFilter]);
 
     const totalPages = Math.max(1, Math.ceil(total / pageSize));
 
@@ -332,6 +334,18 @@ export default function AssetsPage() {
                             </svg>
                         </button>
                     </div>
+                    <select
+                        value={sourceFilter}
+                        onChange={(e) => setSourceFilter(e.target.value)}
+                        title="Filter by the source that first registered the asset"
+                        className="rounded-sm border-0 py-1.5 pl-3 pr-8 text-gray-900 ring-1 ring-inset ring-gray-300 focus:ring-2 focus:ring-inset focus:ring-vulncheck-blue sm:text-sm font-mono"
+                    >
+                        <option value="">All sources</option>
+                        <option value="WAZUH">Wazuh</option>
+                        <option value="NESSUS">Nessus</option>
+                        <option value="INTUNE">Intune / Defender</option>
+                        <option value="MANUAL">Manual</option>
+                    </select>
                     <label className="flex items-center gap-1.5 text-xs font-mono text-gray-600 cursor-pointer whitespace-nowrap" title="INACTIVE assets are always shown (amber badge). Tick to also show operator-retired DECOMMISSIONED assets.">
                         <input
                             type="checkbox"