fix: sidebar menu visibility, model selector cleanup, time format

- Sidebar: restore DropdownMenu for session actions, fix long titles
  pushing button off-screen (add w-0 flex-1, w-full on content div)
- Model selector: remove SiliconFlow models, DeepSeek only
  (deepseek-reasoner default, deepseek-chat alternative)
- Message timestamp: change from HH:mm to yyyy/M/d HH:mm format
- Default model changed to deepseek-reasoner

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

web/src/components/chat/chat-interface.tsx

@@ -15,7 +15,7 @@ import { knowledgeBaseAPI } from "@/lib/api";
 export default function ChatInterface() {
   const [inputMessage, setInputMessage] = useState("");
   const [isComposing, setIsComposing] = useState(false);
-  const [selectedModel, setSelectedModel] = useState("deepseek-chat");
+  const [selectedModel, setSelectedModel] = useState("deepseek-reasoner");
   const [selectedKnowledgeBases, setSelectedKnowledgeBases] = useState<string[]>([]);
   const [systemKnowledgeBases, setSystemKnowledgeBases] = useState<KnowledgeBase[]>([]);
   const [userKnowledgeBases, setUserKnowledgeBases] = useState<KnowledgeBase[]>([]);

web/src/components/chat/message-item.tsx

@@ -253,7 +253,7 @@ export default function MessageItem({ message, selectedModel }: MessageItemProps
               )}
               <span className="text-[10px] text-muted-foreground/50 mx-1">
                 {message.created_at
-                  ? format(new Date(new Date(message.created_at).getTime() + 8 * 60 * 60 * 1000), "HH:mm")
+                  ? format(new Date(message.created_at), "yyyy/M/d HH:mm")
                   : ""}
               </span>
             </div>

web/src/components/chat/model-selector.tsx

@@ -8,10 +8,9 @@ import {
   DropdownMenuItem,
   DropdownMenuTrigger,
   DropdownMenuSeparator,
-  DropdownMenuLabel,
 } from "@/components/ui/dropdown-menu";
 import { Badge } from "@/components/ui/badge";
-import { ChevronDown, Cpu, Zap, Sparkles, Brain } from "lucide-react";
+import { ChevronDown, Cpu, Sparkles, Brain } from "lucide-react";
 import { cn } from "@/lib/utils";
 
 export interface ModelOption {
@@ -29,19 +28,7 @@ interface ModelSelectorProps {
   className?: string;
 }
 
-const modelGroups = [
-  {
-    provider: "deepseek-official",
-    label: "DeepSeek 官方",
-    models: [
-      {
-        id: "deepseek-chat",
-        name: "DeepSeek-V3",
-        description: "DeepSeek 最新通用模型，速度快、能力强",
-        provider: "deepseek-official",
-        providerLabel: "DeepSeek",
-        icon: Sparkles,
-      },
+const models: ModelOption[] = [
   {
     id: "deepseek-reasoner",
     name: "DeepSeek-R1",
@@ -50,34 +37,16 @@ const modelGroups = [
     providerLabel: "DeepSeek",
     icon: Brain,
   },
-    ],
-  },
   {
-    provider: "siliconflow",
-    label: "SiliconFlow（硅基流动）",
-    models: [
-      {
-        id: "deepseek-ai/DeepSeek-V3",
+    id: "deepseek-chat",
     name: "DeepSeek-V3",
-        description: "通过硅基流动调用，稳定的推理能力",
-        provider: "siliconflow",
-        providerLabel: "硅基流动",
+    description: "通用模型，速度快、能力强",
+    provider: "deepseek-official",
+    providerLabel: "DeepSeek",
     icon: Sparkles,
   },
-      {
-        id: "Qwen/QwQ-32B",
-        name: "QwQ-32B",
-        description: "Qwen 推理模型，高效准确",
-        provider: "siliconflow",
-        providerLabel: "硅基流动",
-        icon: Zap,
-      },
-    ],
-  },
 ];
 
-const allModels = modelGroups.flatMap((g) => g.models);
-
 export default function ModelSelector({
   selectedModel,
   onModelChange,
@@ -86,7 +55,7 @@ export default function ModelSelector({
   const [isOpen, setIsOpen] = useState(false);
 
   const selectedModelData =
-    allModels.find((model) => model.id === selectedModel) || allModels[0];
+    models.find((model) => model.id === selectedModel) || models[0];
   const IconComponent = selectedModelData.icon || Cpu;
 
   return (
@@ -107,17 +76,12 @@ export default function ModelSelector({
           <ChevronDown className="w-3 h-3 ml-1 opacity-50" />
         </Button>
       </DropdownMenuTrigger>
-      <DropdownMenuContent align="start" className="w-72">
+      <DropdownMenuContent align="start" className="w-64">
         <div className="px-2 py-1.5 text-xs font-medium text-muted-foreground">
           选择AI模型
         </div>
         <DropdownMenuSeparator />
-        {modelGroups.map((group) => (
-          <div key={group.provider}>
-            <DropdownMenuLabel className="text-xs text-muted-foreground/70 font-normal px-2 pt-2">
-              {group.label}
-            </DropdownMenuLabel>
-            {group.models.map((model) => {
+        {models.map((model) => {
           const ModelIcon = model.icon || Cpu;
           const isSelected = model.id === selectedModel;
 
@@ -150,8 +114,6 @@ export default function ModelSelector({
             </DropdownMenuItem>
           );
         })}
-          </div>
-        ))}
       </DropdownMenuContent>
     </DropdownMenu>
   );

web/src/components/chat/sidebar.tsx

@@ -12,7 +12,14 @@ import {
   Trash2,
   Download,
   Search,
+  MoreVertical,
 } from "lucide-react";
+import {
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuTrigger,
+} from "@/components/ui/dropdown-menu";
 import {
   Dialog,
   DialogContent,
@@ -109,7 +116,6 @@ export default function Sidebar({ onClose }: SidebarProps) {
   const groups = groupSessionsByDate(filteredSessions());
 
   return (
-    <>
     <div className="flex flex-col h-full">
       {/* Header */}
       <div className="px-3 pt-4 pb-3 space-y-3 border-b border-border/30">
@@ -130,9 +136,9 @@ export default function Sidebar({ onClose }: SidebarProps) {
         </div>
       </div>
 
-        {/* Session list with date groups */}
+      {/* Session list */}
       <ScrollArea className="flex-1 px-2">
-          <div className="pb-4">
+        <div className="pb-4 w-full">
           {groups.map(group => (
             <div key={group.label} className="mb-3">
               <div className="px-2 py-1.5 text-xs font-medium text-muted-foreground/70 uppercase tracking-wider">
@@ -142,46 +148,39 @@ export default function Sidebar({ onClose }: SidebarProps) {
                 {group.sessions.map(session => (
                   <div
                     key={session.id}
-                      className="relative rounded-lg cursor-pointer transition-colors hover:bg-muted/50"
-                      style={{
-                        backgroundColor: currentSession?.id === session.id ? 'var(--muted)' : undefined,
-                        color: currentSession?.id === session.id ? 'var(--foreground)' : undefined
-                      }}
+                    className={`group relative flex items-center gap-2 px-2.5 py-2 rounded-lg cursor-pointer transition-colors hover:bg-muted/50 overflow-hidden ${
+                      currentSession?.id === session.id ? 'bg-muted' : ''
+                    }`}
                     onClick={() => handleSelectSession(session.id)}
                   >
-                      {/* Title row */}
-                      <div className="flex items-center gap-2 px-2.5 py-2 pr-28">
                     <MessageSquare className="w-3.5 h-3.5 text-muted-foreground flex-shrink-0" />
-                        <span className="text-sm truncate">{session.title}</span>
-                      </div>
+                    <span className="text-sm truncate min-w-0 w-0 flex-1">{session.title}</span>
 
-                      {/* Action buttons — absolute positioned, always visible */}
-                      <div
-                        className="absolute right-1.5 top-1/2 -translate-y-1/2 flex items-center gap-1"
-                        onClick={(e) => e.stopPropagation()}
-                      >
-                        <button
-                          className="inline-flex items-center justify-center w-7 h-7 rounded-md text-gray-500 hover:text-gray-800 hover:bg-gray-200 transition-colors"
-                          title="重命名"
-                          onClick={() => { setEditingSession(session.id); setEditTitle(session.title); }}
-                        >
-                          <Edit2 className="w-3.5 h-3.5" />
-                        </button>
-                        <ExportDialog sessionId={session.id} sessionTitle={session.title} onClose={() => {}}>
-                          <button
-                            className="inline-flex items-center justify-center w-7 h-7 rounded-md text-gray-500 hover:text-gray-800 hover:bg-gray-200 transition-colors"
-                            title="导出"
-                          >
-                            <Download className="w-3.5 h-3.5" />
+                    {/* Dropdown menu — visible on hover */}
+                    <div className="flex-shrink-0" onClick={(e) => e.stopPropagation()}>
+                      <DropdownMenu>
+                        <DropdownMenuTrigger asChild>
+                          <button className="h-6 w-6 inline-flex items-center justify-center rounded-md text-muted-foreground hover:text-foreground hover:bg-muted transition-all">
+                            <MoreVertical className="w-3.5 h-3.5" />
                           </button>
+                        </DropdownMenuTrigger>
+                        <DropdownMenuContent align="end" onClick={(e) => e.stopPropagation()}>
+                          <DropdownMenuItem onSelect={() => { setEditingSession(session.id); setEditTitle(session.title); }}>
+                            <Edit2 className="w-4 h-4 mr-2" />
+                            重命名
+                          </DropdownMenuItem>
+                          <ExportDialog sessionId={session.id} sessionTitle={session.title}>
+                            <DropdownMenuItem onSelect={(e) => e.preventDefault()}>
+                              <Download className="w-4 h-4 mr-2" />
+                              导出
+                            </DropdownMenuItem>
                           </ExportDialog>
-                        <button
-                          className="inline-flex items-center justify-center w-7 h-7 rounded-md text-gray-500 hover:text-red-600 hover:bg-red-50 transition-colors"
-                          title="删除"
-                          onClick={() => setDeleteSessionId(session.id)}
-                        >
-                          <Trash2 className="w-3.5 h-3.5" />
-                        </button>
+                          <DropdownMenuItem onSelect={() => setDeleteSessionId(session.id)} className="text-destructive">
+                            <Trash2 className="w-4 h-4 mr-2" />
+                            删除
+                          </DropdownMenuItem>
+                        </DropdownMenuContent>
+                      </DropdownMenu>
                     </div>
                   </div>
                 ))}
@@ -198,7 +197,7 @@ export default function Sidebar({ onClose }: SidebarProps) {
         </div>
       </ScrollArea>
 
-        {/* Footer — new chat button with distinct background */}
+      {/* Footer */}
       <div className="px-3 py-3 border-t border-border/30 bg-muted/20">
         <Button
           onClick={handleNewChat}
@@ -209,7 +208,6 @@ export default function Sidebar({ onClose }: SidebarProps) {
           新对话
         </Button>
       </div>
-      </div>
 
       {/* Rename dialog */}
       <Dialog open={!!editingSession} onOpenChange={() => { setEditingSession(null); setEditTitle(""); }}>
@@ -222,7 +220,7 @@ export default function Sidebar({ onClose }: SidebarProps) {
               value={editTitle}
               onChange={(e) => setEditTitle(e.target.value)}
               placeholder="对话名称"
-              onKeyDown={(e) => { if (e.key === 'Enter' && editTitle.trim()) handleSaveRename(); }}
+              onKeyDown={(e) => { if (e.key === "Enter" && editTitle.trim()) handleSaveRename(); }}
               autoFocus
             />
           </div>
@@ -246,6 +244,6 @@ export default function Sidebar({ onClose }: SidebarProps) {
           </DialogFooter>
         </DialogContent>
       </Dialog>
-    </>
+    </div>
   );
 }