fix: 组织架构树分支层点击可选中查看成员（评审发现的行为回归）

app/admin/org/page.tsx

@@ -282,22 +282,33 @@ export default function OrgPage() {
                     <div key={node.id}>
                       <button
                         type="button"
-                        onClick={() => (hasChildren ? toggleExpand(node.id) : selectNode(node))}
+                        onClick={() => selectNode(node)}
                         className={`w-full flex items-center gap-2 px-3 py-2 text-left transition-colors ${
                           isSelected ? 'bg-[#e3ecf5]' : 'hover:bg-[#f7f8fa]'
                         }`}
                         style={{ paddingLeft: `${12 + depth * 16}px` }}
                       >
                         {hasChildren ? (
-                          <svg
-                            className={`w-3 h-3 text-[#8a94a0] transition-transform ${isExpanded ? 'rotate-90' : ''}`}
-                            fill="none"
-                            stroke="currentColor"
-                            viewBox="0 0 24 24"
-                            aria-hidden="true"
+                          <span
+                            role="button"
+                            tabIndex={-1}
+                            aria-label={isExpanded ? '收起' : '展开'}
+                            onClick={(e) => {
+                              e.stopPropagation()
+                              toggleExpand(node.id)
+                            }}
+                            className="shrink-0 cursor-pointer"
                           >
-                            <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2.5} d="M9 5l7 7-7 7" />
-                          </svg>
+                            <svg
+                              className={`w-3 h-3 text-[#8a94a0] transition-transform ${isExpanded ? 'rotate-90' : ''}`}
+                              fill="none"
+                              stroke="currentColor"
+                              viewBox="0 0 24 24"
+                              aria-hidden="true"
+                            >
+                              <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2.5} d="M9 5l7 7-7 7" />
+                            </svg>
+                          </span>
                         ) : (
                           <span className="w-3 inline-block" aria-hidden="true" />
                         )}