SQLite Backup 按 CGO build tag 隔离，支持静态编译（Alpine musl）

internal/database/db_backup_nocgo.go

@@ -0,0 +1,9 @@
+//go:build !cgo
+
+package database
+
+import "errors"
+
+func BackupSQLite(dstPath string) error {
+	return errors.New("sqlite backup requires CGO build")
+}