feat: 导入账号时 best-effort 从 id_token 提取用户信息

提取 DecodeIDToken（跳过过期校验）供导入场景使用，
ParseIDToken 复用它并保留原有过期检查行为。
导入 OpenAI/Sora OAuth 账号时自动补充缺失的 email、
plan_type、chatgpt_account_id 等字段，不覆盖已有值。

backend/internal/handler/admin/account_data.go

@@ -8,6 +8,9 @@ import (
 	"strings"
 	"time"
 
+	"log/slog"
+
+	"github.com/Wei-Shaw/sub2api/internal/pkg/openai"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/response"
 	"github.com/Wei-Shaw/sub2api/internal/service"
 	"github.com/gin-gonic/gin"
@@ -292,6 +295,8 @@ func (h *AccountHandler) importData(ctx context.Context, req DataImportRequest)
 			}
 		}
 
+		enrichCredentialsFromIDToken(&item)
+
 		accountInput := &service.CreateAccountInput{
 			Name:                 item.Name,
 			Notes:                item.Notes,
@@ -535,6 +540,57 @@ func defaultProxyName(name string) string {
 	return name
 }
 
+// enrichCredentialsFromIDToken performs best-effort extraction of user info fields
+// (email, plan_type, chatgpt_account_id, etc.) from id_token in credentials.
+// Only applies to OpenAI/Sora OAuth accounts. Skips expired token errors silently.
+// Existing credential values are never overwritten — only missing fields are filled.
+func enrichCredentialsFromIDToken(item *DataAccount) {
+	if item.Credentials == nil {
+		return
+	}
+	// Only enrich OpenAI/Sora OAuth accounts
+	platform := strings.ToLower(strings.TrimSpace(item.Platform))
+	if platform != service.PlatformOpenAI && platform != service.PlatformSora {
+		return
+	}
+	if strings.ToLower(strings.TrimSpace(item.Type)) != service.AccountTypeOAuth {
+		return
+	}
+
+	idToken, _ := item.Credentials["id_token"].(string)
+	if strings.TrimSpace(idToken) == "" {
+		return
+	}
+
+	// DecodeIDToken skips expiry validation — safe for imported data
+	claims, err := openai.DecodeIDToken(idToken)
+	if err != nil {
+		slog.Debug("import_enrich_id_token_decode_failed", "account", item.Name, "error", err)
+		return
+	}
+
+	userInfo := claims.GetUserInfo()
+	if userInfo == nil {
+		return
+	}
+
+	// Fill missing fields only (never overwrite existing values)
+	setIfMissing := func(key, value string) {
+		if value == "" {
+			return
+		}
+		if existing, _ := item.Credentials[key].(string); existing == "" {
+			item.Credentials[key] = value
+		}
+	}
+
+	setIfMissing("email", userInfo.Email)
+	setIfMissing("plan_type", userInfo.PlanType)
+	setIfMissing("chatgpt_account_id", userInfo.ChatGPTAccountID)
+	setIfMissing("chatgpt_user_id", userInfo.ChatGPTUserID)
+	setIfMissing("organization_id", userInfo.OrganizationID)
+}
+
 func normalizeProxyStatus(status string) string {
 	normalized := strings.TrimSpace(strings.ToLower(status))
 	switch normalized {

backend/internal/pkg/openai/oauth.go

@@ -326,12 +326,9 @@ func (r *RefreshTokenRequest) ToFormData() string {
 	return params.Encode()
 }
 
-// ParseIDToken parses the ID Token JWT and extracts claims.
-// 注意：当前仅解码 payload 并校验 exp，未验证 JWT 签名。
-// 生产环境如需用 ID Token 做授权决策，应通过 OpenAI 的 JWKS 端点验证签名：
-//
-//	https://auth.openai.com/.well-known/jwks.json
-func ParseIDToken(idToken string) (*IDTokenClaims, error) {
+// DecodeIDToken decodes the ID Token JWT payload without validating expiration.
+// Use this for best-effort extraction (e.g., during data import) where the token may be expired.
+func DecodeIDToken(idToken string) (*IDTokenClaims, error) {
 	parts := strings.Split(idToken, ".")
 	if len(parts) != 3 {
 		return nil, fmt.Errorf("invalid JWT format: expected 3 parts, got %d", len(parts))
@@ -361,6 +358,20 @@ func ParseIDToken(idToken string) (*IDTokenClaims, error) {
 		return nil, fmt.Errorf("failed to parse JWT claims: %w", err)
 	}
 
+	return &claims, nil
+}
+
+// ParseIDToken parses the ID Token JWT and extracts claims.
+// 注意：当前仅解码 payload 并校验 exp，未验证 JWT 签名。
+// 生产环境如需用 ID Token 做授权决策，应通过 OpenAI 的 JWKS 端点验证签名：
+//
+//	https://auth.openai.com/.well-known/jwks.json
+func ParseIDToken(idToken string) (*IDTokenClaims, error) {
+	claims, err := DecodeIDToken(idToken)
+	if err != nil {
+		return nil, err
+	}
+
 	// 校验 ID Token 是否已过期（允许 2 分钟时钟偏差，防止因服务器时钟略有差异误判刚颁发的令牌）
 	const clockSkewTolerance = 120 // 秒
 	now := time.Now().Unix()
@@ -368,7 +379,7 @@ func ParseIDToken(idToken string) (*IDTokenClaims, error) {
 		return nil, fmt.Errorf("id_token has expired (exp: %d, now: %d, skew_tolerance: %ds)", claims.Exp, now, clockSkewTolerance)
 	}
 
-	return &claims, nil
+	return claims, nil
 }
 
 // UserInfo represents user information extracted from ID Token claims.