feat: improve empty state guidance for first-run experience

Show detailed import instructions and conditionally display common
config snippet hint for Claude/Codex/Gemini (not OpenCode/OpenClaw).

src/components/providers/ProviderEmptyState.tsx

@@ -1,17 +1,22 @@
 import { Download, Users } from "lucide-react";
 import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
+import type { AppId } from "@/lib/api/types";
 
 interface ProviderEmptyStateProps {
+  appId: AppId;
   onCreate?: () => void;
   onImport?: () => void;
 }
 
 export function ProviderEmptyState({
+  appId,
   onCreate,
   onImport,
 }: ProviderEmptyStateProps) {
   const { t } = useTranslation();
+  const showSnippetHint =
+    appId === "claude" || appId === "codex" || appId === "gemini";
 
   return (
     <div className="flex flex-col items-center justify-center rounded-lg border border-dashed border-border p-10 text-center">
@@ -19,9 +24,14 @@ export function ProviderEmptyState({
         <Users className="h-7 w-7 text-muted-foreground" />
       </div>
       <h3 className="text-lg font-semibold">{t("provider.noProviders")}</h3>
-      <p className="mt-2 max-w-sm text-sm text-muted-foreground">
+      <p className="mt-2 max-w-lg text-sm text-muted-foreground">
         {t("provider.noProvidersDescription")}
       </p>
+      {showSnippetHint && (
+        <p className="mt-1 max-w-lg text-sm text-muted-foreground">
+          {t("provider.noProvidersDescriptionSnippet")}
+        </p>
+      )}
       <div className="mt-6 flex flex-col gap-2">
         {onImport && (
           <Button onClick={onImport}>

src/components/providers/ProviderList.tsx

@@ -298,6 +298,7 @@ export function ProviderList({
   if (sortedProviders.length === 0) {
     return (
       <ProviderEmptyState
+        appId={appId}
         onCreate={onCreate}
         onImport={() => importMutation.mutate()}
       />

src/i18n/locales/en.json

@@ -80,7 +80,8 @@
     "tabProvider": "Provider",
     "tabUniversal": "Universal",
     "noProviders": "No providers added yet",
-    "noProvidersDescription": "Import your current live config below, or manually add a new provider",
+    "noProvidersDescription": "If you already have a config, click \"Import Current Config\" — all data will be safely saved in a default provider",
+    "noProvidersDescriptionSnippet": "Settings other than API key and endpoint (e.g. plugins) will be saved to a common config snippet for sharing across providers",
     "importCurrent": "Import Current Config",
     "importCurrentDescription": "Import current live config as default provider",
     "currentlyUsing": "Currently Using",

src/i18n/locales/ja.json

@@ -80,7 +80,8 @@
     "tabProvider": "プロバイダー",
     "tabUniversal": "統一プロバイダー",
     "noProviders": "まだプロバイダーがありません",
-    "noProvidersDescription": "下の「現在の設定をインポート」ボタンで既存の設定を取り込むか、新しいプロバイダーを手動で追加してください",
+    "noProvidersDescription": "既存の設定がある場合は「現在の設定をインポート」をクリックしてください。すべてのデータが default プロバイダーに安全に保存されます",
+    "noProvidersDescriptionSnippet": "API キーとリクエスト URL 以外のデータ（プラグインなど）は共通設定スニペットに保存され、プロバイダー間で共有できます",
     "importCurrent": "現在の設定をインポート",
     "importCurrentDescription": "現在使用中の設定をデフォルトプロバイダーとしてインポート",
     "currentlyUsing": "現在使用中",

src/i18n/locales/zh.json

@@ -80,7 +80,8 @@
     "tabProvider": "供应商",
     "tabUniversal": "统一供应商",
     "noProviders": "还没有添加任何供应商",
-    "noProvidersDescription": "点击下方的\"导入当前配置\"按钮导入已有配置，或手动添加新的供应商",
+    "noProvidersDescription": "如果你已有配置，请点击\"导入当前配置\"，所有数据将安全保存在 default 供应商中",
+    "noProvidersDescriptionSnippet": "除 Key 和请求地址外的数据（如插件配置）会被保存到通用配置片段，用于在不同供应商之间共享",
     "importCurrent": "导入当前配置",
     "importCurrentDescription": "将当前正在使用的配置导入为默认供应商",
     "currentlyUsing": "当前使用",