fix(proxy): resolve UI/UX issues and database constraint error

Simplify proxy control interface and fix database persistence issues:

Backend Fixes:
- Fix NOT NULL constraint error in proxy_config.created_at field
  * Use COALESCE to preserve created_at on updates
  * Ensure proper INSERT OR REPLACE behavior
- Remove redundant enabled field validation on startup
  * Auto-enable when user clicks start button
  * Persist enabled state after successful start
- Preserve enabled state during config updates
  * Prevent accidental service shutdown on config save

Frontend Improvements:
- Remove duplicate proxy enable switch from settings dialog
  * Keep only runtime toggle in ProxyPanel
  * Simplify user experience with single control point
- Hide proxy target button when proxy service is stopped
  * Add isProxyRunning prop to ProviderCard
  * Conditionally render proxy controls based on service status
- Update form schema to omit enabled field
  * Managed automatically by backend

Files: 5 changed, 81 insertions(+), 94 deletions(-)

src/components/providers/ProviderCard.tsx

@@ -31,6 +31,7 @@ interface ProviderCardProps {
   onOpenWebsite: (url: string) => void;
   onDuplicate: (provider: Provider) => void;
   onSetProxyTarget: (provider: Provider) => void;
+  isProxyRunning: boolean;
   dragHandleProps?: DragHandleProps;
 }
 
@@ -80,6 +81,7 @@ export function ProviderCard({
   onOpenWebsite,
   onDuplicate,
   onSetProxyTarget,
+  isProxyRunning,
   dragHandleProps,
 }: ProviderCardProps) {
   const { t } = useTranslation();
@@ -169,41 +171,43 @@ export function ProviderCard({
                   </span>
                 )}
 
-              {/* 代理目标开关 */}
-              <div
-                className="flex items-center gap-2 ml-2"
-                onClick={(e) => e.stopPropagation()}
-              >
-                <Switch
-                  id={`proxy-target-switch-${provider.id}`}
-                  checked={provider.isProxyTarget || false}
-                  onCheckedChange={(checked) => {
-                    if (checked && !provider.isProxyTarget) {
-                      onSetProxyTarget(provider);
-                    }
-                  }}
-                  disabled={provider.isProxyTarget}
-                  className="scale-75 data-[state=checked]:bg-purple-500"
-                />
-                {provider.isProxyTarget && (
-                  <Label
-                    htmlFor={`proxy-target-switch-${provider.id}`}
-                    className="text-xs font-medium text-purple-500 dark:text-purple-400 cursor-pointer"
-                  >
-                    {t("provider.proxyTarget", { defaultValue: "代理目标" })}
-                  </Label>
-                )}
-                {!provider.isProxyTarget && (
-                  <Label
-                    htmlFor={`proxy-target-switch-${provider.id}`}
-                    className="text-xs text-muted-foreground cursor-pointer opacity-0 group-hover:opacity-100 transition-opacity"
-                  >
-                    {t("provider.setAsProxyTarget", {
-                      defaultValue: "设为代理",
-                    })}
-                  </Label>
-                )}
-              </div>
+              {/* 代理目标开关 - 仅在代理服务运行时显示 */}
+              {isProxyRunning && (
+                <div
+                  className="flex items-center gap-2 ml-2"
+                  onClick={(e) => e.stopPropagation()}
+                >
+                  <Switch
+                    id={`proxy-target-switch-${provider.id}`}
+                    checked={provider.isProxyTarget || false}
+                    onCheckedChange={(checked) => {
+                      if (checked && !provider.isProxyTarget) {
+                        onSetProxyTarget(provider);
+                      }
+                    }}
+                    disabled={provider.isProxyTarget}
+                    className="scale-75 data-[state=checked]:bg-purple-500"
+                  />
+                  {provider.isProxyTarget && (
+                    <Label
+                      htmlFor={`proxy-target-switch-${provider.id}`}
+                      className="text-xs font-medium text-purple-500 dark:text-purple-400 cursor-pointer"
+                    >
+                      {t("provider.proxyTarget", { defaultValue: "代理目标" })}
+                    </Label>
+                  )}
+                  {!provider.isProxyTarget && (
+                    <Label
+                      htmlFor={`proxy-target-switch-${provider.id}`}
+                      className="text-xs text-muted-foreground cursor-pointer opacity-0 group-hover:opacity-100 transition-opacity"
+                    >
+                      {t("provider.setAsProxyTarget", {
+                        defaultValue: "设为代理",
+                      })}
+                    </Label>
+                  )}
+                </div>
+              )}
             </div>
 
             {displayUrl && (

src/components/providers/ProviderList.tsx

@@ -9,6 +9,7 @@ import type { CSSProperties } from "react";
 import type { Provider } from "@/types";
 import type { AppId } from "@/lib/api";
 import { useDragSort } from "@/hooks/useDragSort";
+import { useProxyStatus } from "@/hooks/useProxyStatus";
 import { ProviderCard } from "@/components/providers/ProviderCard";
 import { ProviderEmptyState } from "@/components/providers/ProviderEmptyState";
 
@@ -46,6 +47,9 @@ export function ProviderList({
     appId,
   );
 
+  // 获取代理服务运行状态
+  const { isRunning: isProxyRunning } = useProxyStatus();
+
   if (isLoading) {
     return (
       <div className="space-y-3">
@@ -90,6 +94,7 @@ export function ProviderList({
               onConfigureUsage={onConfigureUsage}
               onOpenWebsite={onOpenWebsite}
               onSetProxyTarget={onSetProxyTarget}
+              isProxyRunning={isProxyRunning}
             />
           ))}
         </div>
@@ -109,6 +114,7 @@ interface SortableProviderCardProps {
   onConfigureUsage?: (provider: Provider) => void;
   onOpenWebsite: (url: string) => void;
   onSetProxyTarget: (provider: Provider) => void;
+  isProxyRunning: boolean;
 }
 
 function SortableProviderCard({
@@ -122,6 +128,7 @@ function SortableProviderCard({
   onConfigureUsage,
   onOpenWebsite,
   onSetProxyTarget,
+  isProxyRunning,
 }: SortableProviderCardProps) {
   const {
     setNodeRef,
@@ -152,6 +159,7 @@ function SortableProviderCard({
         }
         onOpenWebsite={onOpenWebsite}
         onSetProxyTarget={onSetProxyTarget}
+        isProxyRunning={isProxyRunning}
         dragHandleProps={{
           attributes,
           listeners,

src/components/proxy/ProxySettingsDialog.tsx

@@ -26,7 +26,8 @@ import { useTranslation } from "react-i18next";
 import type { TFunction } from "i18next";
 import type { ProxyConfig } from "@/types/proxy";
 
-type ProxyConfigForm = ProxyConfig;
+// 表单数据类型（不包含 enabled 字段，该字段由后端自动管理）
+type ProxyConfigForm = Omit<ProxyConfig, "enabled">;
 
 const createProxyConfigSchema = (t: TFunction) => {
   const requestTimeoutSchema = z
@@ -50,7 +51,6 @@ const createProxyConfigSchema = (t: TFunction) => {
     });
 
   return z.object({
-    enabled: z.boolean(),
     listen_address: z.string().regex(
       /^(\d{1,3}\.){3}\d{1,3}$/,
       t("proxy.settings.validation.addressInvalid", {
@@ -108,7 +108,6 @@ export function ProxySettingsDialog({
   const form = useForm<ProxyConfigForm>({
     resolver: zodResolver(schema),
     defaultValues: {
-      enabled: false,
       listen_address: "127.0.0.1",
       listen_port: 5000,
       max_retries: 3,
@@ -128,7 +127,12 @@ export function ProxySettingsDialog({
 
   const onSubmit = async (data: ProxyConfigForm) => {
     try {
-      await updateConfig(data);
+      // 添加 enabled 字段（从当前配置中获取，保持不变）
+      const configToSave: ProxyConfig = {
+        ...data,
+        enabled: config?.enabled ?? true,
+      };
+      await updateConfig(configToSave);
       closePanel();
     } catch (error) {
       console.error("Save config failed:", error);
@@ -196,38 +200,11 @@ export function ProxySettingsDialog({
                 </h3>
                 <p className="text-sm text-muted-foreground">
                   {t("proxy.settings.basic.description", {
-                    defaultValue: "控制代理服务是否启用以及监听的地址与端口。",
+                    defaultValue: "配置代理服务监听的地址与端口。",
                   })}
                 </p>
               </div>
 
-              <FormField
-                control={form.control}
-                name="enabled"
-                render={({ field }) => (
-                  <FormItem className="flex items-center justify-between rounded-lg border border-white/10 bg-background/60 p-4">
-                    <div className="space-y-1">
-                      <FormLabel>
-                        {t("proxy.settings.fields.enabled.label", {
-                          defaultValue: "启用代理服务",
-                        })}
-                      </FormLabel>
-                      <FormDescription>
-                        {t("proxy.settings.fields.enabled.description", {
-                          defaultValue: "开启后可以从命令或 UI 启动代理服务器",
-                        })}
-                      </FormDescription>
-                    </div>
-                    <FormControl>
-                      <Switch
-                        checked={field.value}
-                        onCheckedChange={field.onChange}
-                      />
-                    </FormControl>
-                  </FormItem>
-                )}
-              />
-
               <div className="grid gap-4 md:grid-cols-2">
                 <FormField
                   control={form.control}