feat: 品牌重命名 Sub2API -> TianShuAPI

- 前端: 所有界面显示、i18n 文本、组件中的品牌名称
- 后端: 服务层、设置默认值、邮件模板、安装向导
- 数据库: 迁移脚本注释
- 保持功能完全一致，仅更改品牌名称

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

backend/internal/repository/gemini_token_cache.go

@@ -1,44 +1,44 @@
-package repository
-
-import (
-	"context"
-	"fmt"
-	"time"
-
-	"github.com/Wei-Shaw/sub2api/internal/service"
-
-	"github.com/redis/go-redis/v9"
-)
-
-const (
-	geminiTokenKeyPrefix       = "gemini:token:"
-	geminiRefreshLockKeyPrefix = "gemini:refresh_lock:"
-)
-
-type geminiTokenCache struct {
-	rdb *redis.Client
-}
-
-func NewGeminiTokenCache(rdb *redis.Client) service.GeminiTokenCache {
-	return &geminiTokenCache{rdb: rdb}
-}
-
-func (c *geminiTokenCache) GetAccessToken(ctx context.Context, cacheKey string) (string, error) {
-	key := fmt.Sprintf("%s%s", geminiTokenKeyPrefix, cacheKey)
-	return c.rdb.Get(ctx, key).Result()
-}
-
-func (c *geminiTokenCache) SetAccessToken(ctx context.Context, cacheKey string, token string, ttl time.Duration) error {
-	key := fmt.Sprintf("%s%s", geminiTokenKeyPrefix, cacheKey)
-	return c.rdb.Set(ctx, key, token, ttl).Err()
-}
-
-func (c *geminiTokenCache) AcquireRefreshLock(ctx context.Context, cacheKey string, ttl time.Duration) (bool, error) {
-	key := fmt.Sprintf("%s%s", geminiRefreshLockKeyPrefix, cacheKey)
-	return c.rdb.SetNX(ctx, key, 1, ttl).Result()
-}
-
-func (c *geminiTokenCache) ReleaseRefreshLock(ctx context.Context, cacheKey string) error {
-	key := fmt.Sprintf("%s%s", geminiRefreshLockKeyPrefix, cacheKey)
-	return c.rdb.Del(ctx, key).Err()
-}
+package repository
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/service"
+
+	"github.com/redis/go-redis/v9"
+)
+
+const (
+	geminiTokenKeyPrefix       = "gemini:token:"
+	geminiRefreshLockKeyPrefix = "gemini:refresh_lock:"
+)
+
+type geminiTokenCache struct {
+	rdb *redis.Client
+}
+
+func NewGeminiTokenCache(rdb *redis.Client) service.GeminiTokenCache {
+	return &geminiTokenCache{rdb: rdb}
+}
+
+func (c *geminiTokenCache) GetAccessToken(ctx context.Context, cacheKey string) (string, error) {
+	key := fmt.Sprintf("%s%s", geminiTokenKeyPrefix, cacheKey)
+	return c.rdb.Get(ctx, key).Result()
+}
+
+func (c *geminiTokenCache) SetAccessToken(ctx context.Context, cacheKey string, token string, ttl time.Duration) error {
+	key := fmt.Sprintf("%s%s", geminiTokenKeyPrefix, cacheKey)
+	return c.rdb.Set(ctx, key, token, ttl).Err()
+}
+
+func (c *geminiTokenCache) AcquireRefreshLock(ctx context.Context, cacheKey string, ttl time.Duration) (bool, error) {
+	key := fmt.Sprintf("%s%s", geminiRefreshLockKeyPrefix, cacheKey)
+	return c.rdb.SetNX(ctx, key, 1, ttl).Result()
+}
+
+func (c *geminiTokenCache) ReleaseRefreshLock(ctx context.Context, cacheKey string) error {
+	key := fmt.Sprintf("%s%s", geminiRefreshLockKeyPrefix, cacheKey)
+	return c.rdb.Del(ctx, key).Err()
+}