refactor(frontend): 优化 Gemini 配额显示，参考 Antigravity 样式

- 简化标签：将 "RPD Pro/Flash" 改为 "Pro/Flash"，避免文字截断
- 添加账号类型徽章（Free/Pro/Ultra），带颜色区分
- 添加帮助图标（?），悬停显示限流政策和官方文档链接
- 重构显示布局：账号类型 + 两行配额（Pro/Flash）
- 移除冗余的 AccountQuotaInfo 组件调用

backend/internal/service/account_usage_service.go

@@ -202,22 +202,25 @@ func (s *AccountUsageService) GetUsage(ctx context.Context, accountID int64) (*U
 
 func (s *AccountUsageService) getGeminiUsage(ctx context.Context, account *Account) (*UsageInfo, error) {
 	now := time.Now()
-	start := geminiDailyWindowStart(now)
-
-	stats, err := s.usageLogRepo.GetModelStatsWithFilters(ctx, start, now, 0, 0, account.ID)
-	if err != nil {
-		return nil, fmt.Errorf("get gemini usage stats failed: %w", err)
-	}
-
 	usage := &UsageInfo{
 		UpdatedAt: &now,
 	}
 
+	if s.geminiQuotaService == nil || s.usageLogRepo == nil {
+		return usage, nil
+	}
+
 	quota, ok := s.geminiQuotaService.QuotaForAccount(ctx, account)
 	if !ok {
 		return usage, nil
 	}
 
+	start := geminiDailyWindowStart(now)
+	stats, err := s.usageLogRepo.GetModelStatsWithFilters(ctx, start, now, 0, 0, account.ID)
+	if err != nil {
+		return nil, fmt.Errorf("get gemini usage stats failed: %w", err)
+	}
+
 	totals := geminiAggregateUsage(stats)
 	resetAt := geminiDailyResetTime(now)
 

backend/internal/service/ratelimit_service.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/Wei-Shaw/sub2api/internal/config"
@@ -17,8 +18,18 @@ type RateLimitService struct {
 	usageRepo          UsageLogRepository
 	cfg                *config.Config
 	geminiQuotaService *GeminiQuotaService
+	usageCacheMu       sync.Mutex
+	usageCache         map[int64]*geminiUsageCacheEntry
 }
 
+type geminiUsageCacheEntry struct {
+	windowStart time.Time
+	cachedAt    time.Time
+	totals      GeminiUsageTotals
+}
+
+const geminiPrecheckCacheTTL = time.Minute
+
 // NewRateLimitService 创建RateLimitService实例
 func NewRateLimitService(accountRepo AccountRepository, usageRepo UsageLogRepository, cfg *config.Config, geminiQuotaService *GeminiQuotaService) *RateLimitService {
 	return &RateLimitService{
@@ -26,6 +37,7 @@ func NewRateLimitService(accountRepo AccountRepository, usageRepo UsageLogReposi
 		usageRepo:          usageRepo,
 		cfg:                cfg,
 		geminiQuotaService: geminiQuotaService,
+		usageCache:         make(map[int64]*geminiUsageCacheEntry),
 	}
 }
 
@@ -73,7 +85,7 @@ func (s *RateLimitService) PreCheckUsage(ctx context.Context, account *Account,
 	if account == nil || !account.IsGeminiCodeAssist() || strings.TrimSpace(requestedModel) == "" {
 		return true, nil
 	}
-	if s.usageRepo == nil {
+	if s.usageRepo == nil || s.geminiQuotaService == nil {
 		return true, nil
 	}
 
@@ -95,11 +107,15 @@ func (s *RateLimitService) PreCheckUsage(ctx context.Context, account *Account,
 
 	now := time.Now()
 	start := geminiDailyWindowStart(now)
-	stats, err := s.usageRepo.GetModelStatsWithFilters(ctx, start, now, 0, 0, account.ID)
-	if err != nil {
-		return true, err
+	totals, ok := s.getGeminiUsageTotals(account.ID, start, now)
+	if !ok {
+		stats, err := s.usageRepo.GetModelStatsWithFilters(ctx, start, now, 0, 0, account.ID)
+		if err != nil {
+			return true, err
+		}
+		totals = geminiAggregateUsage(stats)
+		s.setGeminiUsageTotals(account.ID, start, now, totals)
 	}
-	totals := geminiAggregateUsage(stats)
 
 	var used int64
 	switch geminiModelClassFromName(requestedModel) {
@@ -121,6 +137,40 @@ func (s *RateLimitService) PreCheckUsage(ctx context.Context, account *Account,
 	return true, nil
 }
 
+func (s *RateLimitService) getGeminiUsageTotals(accountID int64, windowStart, now time.Time) (GeminiUsageTotals, bool) {
+	s.usageCacheMu.Lock()
+	defer s.usageCacheMu.Unlock()
+
+	if s.usageCache == nil {
+		return GeminiUsageTotals{}, false
+	}
+
+	entry, ok := s.usageCache[accountID]
+	if !ok || entry == nil {
+		return GeminiUsageTotals{}, false
+	}
+	if !entry.windowStart.Equal(windowStart) {
+		return GeminiUsageTotals{}, false
+	}
+	if now.Sub(entry.cachedAt) >= geminiPrecheckCacheTTL {
+		return GeminiUsageTotals{}, false
+	}
+	return entry.totals, true
+}
+
+func (s *RateLimitService) setGeminiUsageTotals(accountID int64, windowStart, now time.Time, totals GeminiUsageTotals) {
+	s.usageCacheMu.Lock()
+	defer s.usageCacheMu.Unlock()
+	if s.usageCache == nil {
+		s.usageCache = make(map[int64]*geminiUsageCacheEntry)
+	}
+	s.usageCache[accountID] = &geminiUsageCacheEntry{
+		windowStart: windowStart,
+		cachedAt:    now,
+		totals:      totals,
+	}
+}
+
 // GeminiCooldown returns the fallback cooldown duration for Gemini 429s based on tier.
 func (s *RateLimitService) GeminiCooldown(ctx context.Context, account *Account) time.Duration {
 	if account == nil {

backend/migrations/017_add_gemini_tier_id.sql

@@ -26,5 +26,10 @@ UPDATE accounts
 SET credentials = credentials - 'tier_id'
 WHERE platform = 'gemini'
   AND type = 'oauth'
-  AND credentials->>'oauth_type' = 'code_assist';
+  AND jsonb_typeof(credentials) = 'object'
+  AND credentials->>'tier_id' = 'LEGACY'
+  AND (
+    credentials->>'oauth_type' = 'code_assist'
+    OR (credentials->>'oauth_type' IS NULL AND credentials->>'project_id' IS NOT NULL)
+  );
 -- +goose StatementEnd