feat: continue tree rust family cutover

- add rust renderer/state-family scaffolds and inline compat host thinning for page tree, file tree, and picker
- route tree/filetree preflight, file projection, resource artifact, and stream delta contracts through rust plans
- preserve canonical move-order validation, file-tree search projection, and related frontend/runtime regression coverage

wolai-frontend/src/components/sidebar/tree-shell-surface.tsx

@@ -46,7 +46,6 @@ type SidebarFileTreeSurfaceProps = {
   rows?: FileTreeRow[];
   treeShellItems?: KernelFileTreeProjectionItem[];
   activeId: string;
-  selectedRowIds: Set<string>;
   className?: string;
   onRowClick: (row: FileTreeRow, event: MouseEvent) => void;
   onRowDoubleClick: (row: FileTreeRow, event: MouseEvent) => void;