chore: standardize project comments in English

internal/store/backup.go

@@ -9,7 +9,7 @@ import (
 	"strings"
 )
 
-// Snapshot 使用 SQLite 生成一致的独立数据库，不复制活动 WAL 文件。
+// Snapshot uses SQLite to create a consistent standalone database rather than copying active WAL files.
 func (s *Store) Snapshot(ctx context.Context, dest string) error {
 	_, err := s.db.ExecContext(ctx, `VACUUM INTO ?`, dest)
 	return err
@@ -34,7 +34,7 @@ func (s *Store) Preferences() (map[string]json.RawMessage, error) {
 	return result, rows.Err()
 }
 
-// ReplacePreferences 一次提交全部偏好，账户与会话不属于设置包。
+// ReplacePreferences commits all preferences together; accounts and sessions are excluded from settings archives.
 func (s *Store) ReplacePreferences(values map[string]json.RawMessage) error {
 	tx, err := s.db.Begin()
 	if err != nil {
@@ -60,7 +60,7 @@ func (s *Store) ResetPreferences() error {
 }
 func (s *Store) ClearSessions() error { _, err := s.db.Exec(`DELETE FROM sessions`); return err }
 
-// CheckBackup 确认数据库可读取且包含当前版本所需表；不会初始化或修复传入文件。
+// CheckBackup verifies readability and required tables without initializing or repairing the supplied database.
 func (s *Store) CheckBackup() error {
 	var result string
 	if err := s.db.QueryRow(`PRAGMA quick_check`).Scan(&result); err != nil {
@@ -81,7 +81,7 @@ func (s *Store) CheckBackup() error {
 	return nil
 }
 
-// OpenExisting 只打开已有库；导入校验不得创建表或更改日志模式。
+// OpenExisting opens only existing databases; import validation must not create tables or change journal modes.
 func OpenExisting(path string) (*Store, error) {
 	db, err := sql.Open("sqlite", (&url.URL{Scheme: "file", Path: path, RawQuery: "mode=rw&_pragma=busy_timeout(5000)"}).String())
 	if err != nil {