feat: add configurable provider endpoint for codex-api accounts

Add providerEndpoint field (responses/completions/auto) to openai-responses
accounts, allowing admins to specify which API endpoint format the provider
supports. The relay service normalizes request paths based on this config:
- responses (default): routes all requests to /v1/responses
- completions: routes all requests to /v1/chat/completions
- auto: preserves the original request path

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/services/account/openaiResponsesAccountService.js

@@ -51,7 +51,8 @@ class OpenAIResponsesAccountService {
       dailyQuota = 0, // 每日额度限制（美元），0表示不限制
       quotaResetTime = '00:00', // 额度重置时间（HH:mm格式）
       rateLimitDuration = 60, // 限流时间（分钟）
-      disableAutoProtection = false // 是否关闭自动防护（429/401/400/529 不自动禁用）
+      disableAutoProtection = false, // 是否关闭自动防护（429/401/400/529 不自动禁用）
+      providerEndpoint = 'responses' // Provider 端点类型：responses | completions | auto
     } = options
 
     // 验证必填字段
@@ -96,7 +97,8 @@ class OpenAIResponsesAccountService {
       lastResetDate: redis.getDateStringInTimezone(),
       quotaResetTime,
       quotaStoppedAt: '',
-      disableAutoProtection: disableAutoProtection.toString() // 关闭自动防护
+      disableAutoProtection: disableAutoProtection.toString(), // 关闭自动防护
+      providerEndpoint // Provider 端点类型：responses(默认) | completions | auto
     }
 
     // 保存到 Redis