Enhance AssistantConfig and pipeline for FastGPT integration

- Add new fields in AssistantConfig for FastGPT connection details, including `fastgpt_api_url`, `fastgpt_api_key`, and `fastgpt_app_id`.
- Update the pipeline to utilize the new FastGPT configuration, ensuring proper integration with external services.
- Introduce type handling for different assistant types, including support for realtime modes and external brain management.
- Refactor frontend components to include hints for FastGPT configuration inputs, improving user guidance during setup.

frontend/src/components/pages/AssistantPage.tsx

@@ -1419,18 +1419,27 @@ export function AssistantPage(props: AssistantPageProps) {
             >
               <InputField
                 label="App ID"
+                hint={
+                  "FastGPT 应用的 appId，用于拉取应用预设开场白等信息。\n在 FastGPT「应用详情 → 发布渠道 / API 访问」中获取。\n留空则不展示应用开场白，回退使用本助手自身的开场白。"
+                }
                 value={fastGptForm.appId}
                 onChange={(value) => updateFastGptForm("appId", value)}
                 placeholder="请输入 FastGPT 应用 ID"
               />
               <InputField
                 label="API URL"
+                hint={
+                  "填 FastGPT 服务的主机根地址即可，例如 http://localhost:3000。\n系统会自动拼接 /api/v1/chat/completions，无需手动带上该路径。\n（即使粘贴了完整接口地址也会自动归一,但建议只填根地址。）"
+                }
                 value={fastGptForm.apiUrl}
                 onChange={(value) => updateFastGptForm("apiUrl", value)}
-                placeholder="https://api.fastgpt.in/api/v1/chat/completions"
+                placeholder="http://localhost:3000"
               />
               <SecretInputField
                 label="API Key"
+                hint={
+                  "FastGPT 为该应用生成的 API Key（形如 fastgpt-xxxxx）。\n在 FastGPT「应用详情 → API 访问」中创建。每个应用的 Key 独立。"
+                }
                 value={fastGptForm.apiKey}
                 onChange={(value) => updateFastGptForm("apiKey", value)}
                 placeholder="请输入 FastGPT API Key"
@@ -2529,12 +2538,14 @@ function SectionCard({
 
 function InputField({
   label,
+  hint,
   value,
   placeholder,
   type = "text",
   onChange,
 }: {
   label?: string;
+  hint?: string;
   value: string;
   placeholder?: string;
   type?: string;
@@ -2543,7 +2554,10 @@ function InputField({
   return (
     <label className="block">
       {label && (
-        <div className="mb-2 text-sm font-medium text-foreground">{label}</div>
+        <div className="mb-2 flex items-center gap-1.5 text-sm font-medium text-foreground">
+          <span>{label}</span>
+          {hint && <HelpHint text={hint} />}
+        </div>
       )}
       <Input
         value={value}
@@ -2558,12 +2572,14 @@ function InputField({
 
 function SecretInputField({
   label,
+  hint,
   value,
   placeholder,
   storedValueMask,
   onChange,
 }: {
   label?: string;
+  hint?: string;
   value: string;
   placeholder?: string;
   storedValueMask: string;
@@ -2575,7 +2591,10 @@ function SecretInputField({
   return (
     <label className="block">
       {label && (
-        <div className="mb-2 text-sm font-medium text-foreground">{label}</div>
+        <div className="mb-2 flex items-center gap-1.5 text-sm font-medium text-foreground">
+          <span>{label}</span>
+          {hint && <HelpHint text={hint} />}
+        </div>
       )}
       {hasStoredValue && (
         <div className="mb-2 flex items-center gap-2 text-xs text-muted-foreground">