feat(dashboard): file double-click also navigates the graph

Double-clicking a file in the Files tab previously only opened the source
viewer; the graph stayed wherever it was. Now also calls navigateToNode
first (drills into the layer + selects the node), then re-opens the code
viewer so the source panel stays visible.

Order matters: navigateToNodeInLayer resets codeViewerOpen, so the
openCodeViewer call has to come after.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

understand-anything-plugin/packages/dashboard/src/components/FileExplorer.tsx

@@ -141,9 +141,17 @@ function FileTreeRow({
 export default function FileExplorer() {
   const graph = useDashboardStore((s) => s.graph);
   const openCodeViewer = useDashboardStore((s) => s.openCodeViewer);
+  const navigateToNode = useDashboardStore((s) => s.navigateToNode);
   const entries = useMemo(() => buildFileTree(graph?.nodes ?? []), [graph]);
   const [expanded, setExpanded] = useState<Set<string>>(() => new Set());
 
+  // Navigate the graph first (drills into layer + selects node, which clears the
+  // code viewer), then re-open the viewer so the source panel stays visible.
+  const handleOpenFile = (nodeId: string) => {
+    navigateToNode(nodeId);
+    openCodeViewer(nodeId);
+  };
+
   const toggleFolder = (folderPath: string) => {
     setExpanded((current) => {
       const next = new Set(current);
@@ -194,7 +202,7 @@ export default function FileExplorer() {
               depth={0}
               expanded={expanded}
               toggleFolder={toggleFolder}
-              openFile={openCodeViewer}
+              openFile={handleOpenFile}
             />
           ))
         )}