feat: add Codex API headless authentication and proxy configuration UI.

backend/internal/auth/codex_api.go

@@ -492,6 +492,7 @@ func (c *CodexAPIAuth) ObtainAuthorizationCode() (string, error) {
 		verifyHeaders["OpenAI-Sentinel-Token"] = c.getSentinelHeader("password_verify")
 
 		passwordPayload := map[string]string{
+			"username": c.email,
 			"password": c.password,
 		}
 
@@ -500,6 +501,7 @@ func (c *CodexAPIAuth) ObtainAuthorizationCode() (string, error) {
 			c.logError(StepInputPassword, "密码验证失败: %d - %s", resp.StatusCode, string(body[:min(200, len(body))]))
 			return "", fmt.Errorf("密码验证失败: %d", resp.StatusCode)
 		}
+		c.logStep(StepInputPassword, "密码验证成功")
 
 		// 解析密码验证响应
 		json.Unmarshal(body, &data)