fix: enhance proxy configuration with password preservation and UI improvements

- Add 'enabled' field to ProxyConfig for preserving config when disabled
- Mask proxy password in API responses (return '***' instead of actual password)
- Preserve existing password on update when new password not provided
- Add URL encoding for proxy credentials (handle special chars like @, :, /)
- Enhanced URL validation: block SOCKS4, require valid host, forbid embedded auth
- UI improvements: use Switch component, dynamic password placeholder
- Add confirmation dialog for orphaned credentials (URL empty but has username/password)
- Prevent browser password autofill with randomized IDs and CSS text-security
- Unify ProxyConfig type definition in types.ts

frontend/src/api/endpoints/endpoints.ts

@@ -1,14 +1,5 @@
 import client from '../client'
-import type { ProviderEndpoint } from './types'
-
-/**
- * 代理配置类型
- */
-export interface ProxyConfig {
-  url: string
-  username?: string
-  password?: string
-}
+import type { ProviderEndpoint, ProxyConfig } from './types'
 
 /**
  * 获取指定 Provider 的所有 Endpoints
@@ -47,7 +38,7 @@ export async function createEndpoint(
     rate_limit?: number
     is_active?: boolean
     config?: Record<string, any>
-    proxy?: ProxyConfig
+    proxy?: ProxyConfig | null
   }
 ): Promise<ProviderEndpoint> {
   const response = await client.post(`/api/admin/endpoints/providers/${providerId}/endpoints`, data)
@@ -73,7 +64,7 @@ export async function updateEndpoint(
     rate_limit: number
     is_active: boolean
     config: Record<string, any>
-    proxy: ProxyConfig
+    proxy: ProxyConfig | null
   }>
 ): Promise<ProviderEndpoint> {
   const response = await client.put(`/api/admin/endpoints/${endpointId}`, data)

frontend/src/api/endpoints/types.ts

@@ -20,6 +20,16 @@ export const API_FORMAT_LABELS: Record<string, string> = {
   [API_FORMATS.GEMINI_CLI]: 'Gemini CLI',
 }
 
+/**
+ * 代理配置类型
+ */
+export interface ProxyConfig {
+  url: string
+  username?: string
+  password?: string
+  enabled?: boolean  // 是否启用代理（false 时保留配置但不使用）
+}
+
 export interface ProviderEndpoint {
   id: string
   provider_id: string
@@ -41,11 +51,7 @@ export interface ProviderEndpoint {
   last_failure_at?: string
   is_active: boolean
   config?: Record<string, any>
-  proxy?: {
-    url: string
-    username?: string
-    password?: string
-  }
+  proxy?: ProxyConfig | null
   total_keys: number
   active_keys: number
   created_at: string