feat: add save feedback prompts, featured agent fields, dynamic Dify API config, and chat improvements

- Add success/error feedback messages near submit buttons in all admin forms
- Display success prompt for 1s before redirect after save
- Show API error details on save failure
- Add isFeatured/featuredOrder fields to Agent model and admin UI
- Add difyApiUrl/difyApiKey fields for per-agent Dify API configuration
- Show featured badge column in agent admin list
- Display featured agents on homepage sorted by order
- Refactor chat page streaming with AbortController and stable userId
- Improve Dify API proxy to use per-agent credentials

app/admin/agents/AgentForm.tsx

@@ -18,7 +18,11 @@ export default function AgentForm({
     features?: string
     hotQuestions?: string
     quickQuestions?: string
+    difyApiUrl?: string
+    difyApiKey?: string
     status?: string
+    isFeatured?: boolean
+    featuredOrder?: number
   }
 }) {
   const router = useRouter()
@@ -31,10 +35,15 @@ export default function AgentForm({
     features: agent?.features || "",
     hotQuestions: agent?.hotQuestions ? JSON.parse(agent.hotQuestions).join('\n') : '',
     quickQuestions: agent?.quickQuestions ? JSON.parse(agent.quickQuestions).join('\n') : '',
+    difyApiUrl: agent?.difyApiUrl || "",
+    difyApiKey: agent?.difyApiKey || "",
     status: agent?.status || "active",
+    isFeatured: agent?.isFeatured ?? false,
+    featuredOrder: agent?.featuredOrder ?? 0,
   })
   const [loading, setLoading] = useState(false)
   const [error, setError] = useState("")
+  const [success, setSuccess] = useState(false)
 
   const handleSubmit = async (e: React.FormEvent) => {
     e.preventDefault()
@@ -50,6 +59,8 @@ export default function AgentForm({
 
       const body = {
         ...formData,
+        isFeatured: formData.isFeatured,
+        featuredOrder: formData.featuredOrder,
         hotQuestions: JSON.stringify(formData.hotQuestions.split('\n').filter(q => q.trim())),
         quickQuestions: JSON.stringify(formData.quickQuestions.split('\n').filter(q => q.trim())),
       }
@@ -61,9 +72,12 @@ export default function AgentForm({
       })
 
       if (res.ok) {
+        setSuccess(true)
+        await new Promise(r => setTimeout(r, 1000))
         router.push("/admin/agents")
       } else {
-        setError("保存失败")
+        const data = await res.json().catch(() => ({}))
+        setError(data.error || "保存失败")
       }
     } catch (err) {
       setError("保存失败，请稍后重试")
@@ -185,6 +199,34 @@ export default function AgentForm({
         />
       </div>
 
+      <div className="bg-orange-50 border border-orange-200 rounded-xl p-4">
+        <h3 className="text-sm font-semibold text-orange-800 mb-3">热门智能体配置</h3>
+        <div className="grid grid-cols-1 md:grid-cols-2 gap-6">
+          <label className="flex items-center gap-3 cursor-pointer">
+            <input
+              type="checkbox"
+              checked={formData.isFeatured}
+              onChange={(e) => setFormData({ ...formData, isFeatured: e.target.checked })}
+              className="w-5 h-5 text-orange-600 border-gray-300 rounded focus:ring-orange-500"
+            />
+            <span className="text-sm font-medium text-gray-700">设为热门智能体（展示在首页热门区域）</span>
+          </label>
+          <div>
+            <label className="block text-sm font-medium text-gray-700 mb-2">
+              排序（数字越小越靠前）
+            </label>
+            <input
+              type="number"
+              min={0}
+              value={formData.featuredOrder}
+              onChange={(e) => setFormData({ ...formData, featuredOrder: parseInt(e.target.value) || 0 })}
+              className="w-full px-4 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500"
+              placeholder="0"
+            />
+          </div>
+        </div>
+      </div>
+
       <div className="grid grid-cols-1 md:grid-cols-2 gap-6">
         <div>
           <label className="block text-sm font-medium text-gray-700 mb-2">
@@ -212,10 +254,49 @@ export default function AgentForm({
         </div>
       </div>
 
+      <div className="grid grid-cols-1 md:grid-cols-2 gap-6">
+        <div>
+          <label className="block text-sm font-medium text-gray-700 mb-2">
+            Dify API 地址
+          </label>
+          <input
+            type="text"
+            value={formData.difyApiUrl}
+            onChange={(e) => setFormData({ ...formData, difyApiUrl: e.target.value })}
+            className="w-full px-4 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500"
+            placeholder="https://api.dify.ai/v1"
+          />
+        </div>
+        <div>
+          <label className="block text-sm font-medium text-gray-700 mb-2">
+            Dify API Key
+          </label>
+          <input
+            type="password"
+            value={formData.difyApiKey}
+            onChange={(e) => setFormData({ ...formData, difyApiKey: e.target.value })}
+            className="w-full px-4 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500"
+            placeholder="app-xxxxxxxxxxxx"
+          />
+        </div>
+      </div>
+
+      {success && (
+        <div className="bg-green-50 border border-green-200 text-green-700 px-4 py-3 rounded-lg text-sm">
+          保存成功
+        </div>
+      )}
+
+      {error && (
+        <div className="bg-red-50 border border-red-200 text-red-700 px-4 py-3 rounded-lg text-sm">
+          {error}
+        </div>
+      )}
+
       <div className="flex gap-4">
         <button
           type="submit"
-          disabled={loading}
+          disabled={loading || success}
           className="bg-blue-600 text-white px-6 py-2 rounded-lg hover:bg-blue-700 disabled:bg-blue-400"
         >
           {loading ? "保存中..." : "保存"}

app/admin/agents/[id]/edit/page.tsx

@@ -51,7 +51,11 @@ export default async function EditAgentPage({
               features: agent.features,
               hotQuestions: agent.hotQuestions,
               quickQuestions: agent.quickQuestions,
+              difyApiUrl: agent.difyApiUrl || "",
+              difyApiKey: agent.difyApiKey || "",
               status: agent.status,
+              isFeatured: agent.isFeatured,
+              featuredOrder: agent.featuredOrder,
             }}
           />
         </div>

app/admin/agents/page.tsx

@@ -39,6 +39,7 @@ export default async function AdminAgentsPage() {
               <tr>
                 <th className="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase">名称</th>
                 <th className="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase">分类</th>
+                <th className="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase">热门</th>
                 <th className="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase">状态</th>
                 <th className="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase">使用次数</th>
                 <th className="px-6 py-3 text-right text-xs font-medium text-gray-500 uppercase">操作</th>
@@ -59,6 +60,15 @@ export default async function AdminAgentsPage() {
                   <td className="px-6 py-4 text-sm text-gray-600">
                     {agent.category?.name || "-"}
                   </td>
+                  <td className="px-6 py-4">
+                    {agent.isFeatured ? (
+                      <span className="inline-flex px-2 py-1 text-xs font-medium rounded-full bg-orange-100 text-orange-700">
+                        热门
+                      </span>
+                    ) : (
+                      <span className="text-sm text-gray-400">-</span>
+                    )}
+                  </td>
                   <td className="px-6 py-4">
                     <span className={`inline-flex px-2 py-1 text-xs font-medium rounded-full ${
                       agent.status === "active"