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/pagination.go

@@ -1,16 +1,16 @@
-package repository
-
-import "github.com/Wei-Shaw/sub2api/internal/pkg/pagination"
-
-func paginationResultFromTotal(total int64, params pagination.PaginationParams) *pagination.PaginationResult {
-	pages := int(total) / params.Limit()
-	if int(total)%params.Limit() > 0 {
-		pages++
-	}
-	return &pagination.PaginationResult{
-		Total:    total,
-		Page:     params.Page,
-		PageSize: params.Limit(),
-		Pages:    pages,
-	}
-}
+package repository
+
+import "github.com/Wei-Shaw/sub2api/internal/pkg/pagination"
+
+func paginationResultFromTotal(total int64, params pagination.PaginationParams) *pagination.PaginationResult {
+	pages := int(total) / params.Limit()
+	if int(total)%params.Limit() > 0 {
+		pages++
+	}
+	return &pagination.PaginationResult{
+		Total:    total,
+		Page:     params.Page,
+		PageSize: params.Limit(),
+		Pages:    pages,
+	}
+}