fix(pages): 收紧部署包与 Agent 同步边界

完成 V2 Phase 0 安全与一致性前置：统一真实归档限额、流式拉取、候选裁剪、保留上传删除语义及 Pages 路由引用锁。

internal/apps/upload/shared/constants.go

@@ -17,4 +17,6 @@ const (
 	FileStatsTrendDays      = 7
 	MaxS3KeyLength          = 1024
 	AccessCacheTTL          = 5 // seconds; multiplied by time.Second at use site
+	// ReservedPagesDeploymentType is managed exclusively by the Pages domain.
+	ReservedPagesDeploymentType = "openflare_pages_deployment"
 )

internal/apps/upload/shared/errs.go

@@ -27,6 +27,7 @@ const (
 	ErrQueryFileCountFailed            = "查询文件数量失败"
 	ErrQueryFileListFailed             = "查询文件列表失败"
 	ErrDeleteFileFailed                = "删除文件失败"
+	ErrReservedUploadType              = "系统保留的文件类型不能通过通用文件接口操作"
 	ErrStorageReadOnly                 = "存储迁移维护中，当前仅允许读取文件"
 	ErrS3KeyRequired                   = "s3 key must not be empty"
 	ErrS3KeyTooLongFormat              = "s3 key exceeds maximum length of %d"