feat: hover rename/delete icons in treeview, resizable tree and sidebar panels

frontend/src/pages/AIAssistant.tsx

@@ -1,6 +1,7 @@
 import React, { useState, useEffect } from 'react';
 import { SessionList } from '@/components/ai/SessionList';
 import { ChatWindow } from '@/components/ai/ChatWindow';
+import { ResizablePanel } from '@/components/ui/ResizablePanel';
 import { usePluginToolbarStore } from '@/store/pluginToolbarStore';
 import { fetchAgents, type AIAgent } from '@/api/ai';
 
@@ -69,8 +70,16 @@ export function AIAssistantPage() {
   return (
     <div className="flex h-full" data-testid="ai-assistant-page">
       {/* Desktop: two-pane layout */}
-      <div className="hidden md:flex w-72 flex-shrink-0 border-r border-secondary-200 bg-white flex-col">
-        <SessionList key={refreshKey} activeSessionId={activeSessionId} onSelectSession={setActiveSessionId} className="flex-1" />
+      <div className="hidden md:flex">
+        <ResizablePanel
+          initialWidth={288}
+          minWidth={200}
+          maxWidth={500}
+          className="border-r border-secondary-200 bg-white"
+          data-testid="ai-session-pane"
+        >
+          <SessionList key={refreshKey} activeSessionId={activeSessionId} onSelectSession={setActiveSessionId} className="h-full" />
+        </ResizablePanel>
       </div>
       <div className="hidden md:flex flex-1 flex-col">
         {activeSessionId ? <ChatWindow sessionId={activeSessionId} agentId={selectedAgentId} className="flex-1" /> : (