Fix bugs found in full security and stability audit.

Harden artifact paths and fusion uploads, repair pool reconnect and login ID tracking, fix agent/fusion/frontend regressions, and refresh PROBLEMS.md with the full findings list.

server/web/src/components/Fleet/FleetToolbar.tsx

@@ -9,6 +9,8 @@ interface Props {
   onChange: (next: FleetFilterState) => void;
   selectedCount: number;
   onBulkAction: (action: string) => void;
+  onSelectAllFiltered?: () => void;
+  filteredCount?: number;
   bulkBusy: boolean;
 }
 
@@ -18,6 +20,8 @@ export default function FleetToolbar({
   onChange,
   selectedCount,
   onBulkAction,
+  onSelectAllFiltered,
+  filteredCount,
   bulkBusy,
 }: Props) {
   const tags = collectFleetTags(agents);
@@ -78,6 +82,14 @@ export default function FleetToolbar({
         </label>
       </div>
 
+      {onSelectAllFiltered && (filteredCount ?? 0) > 0 && selectedCount === 0 && (
+        <div className="fleet-bulk-bar">
+          <button type="button" className="btn btn-outline btn-sm" onClick={onSelectAllFiltered}>
+            Select all filtered ({filteredCount})
+          </button>
+        </div>
+      )}
+
       {selectedCount > 0 && (
         <div className="fleet-bulk-bar">
           <span className="font-tech">{selectedCount} selected</span>