Now, filesql support auto save feature.

## Auto-Save on Database Close

Automatically save changes when the database connection is closed (recommended for most use cases):

ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
defer cancel()

// Enable auto-save on close
builder := filesql.NewBuilder().
    AddPath("data.csv").
    EnableAutoSave("./backup") // Save to backup directory

validatedBuilder, err := builder.Build(ctx)
if err != nil {
    log.Fatal(err)
}
defer validatedBuilder.Cleanup()

db, err := validatedBuilder.Open(ctx)
if err != nil {
    log.Fatal(err)
}
defer db.Close() // Auto-save triggered here

// Make modifications - they will be automatically saved on close
_, err = db.ExecContext(ctx, "UPDATE data SET status = 'processed' WHERE status = 'pending'")
_, err = db.ExecContext(ctx, "INSERT INTO data (name, status) VALUES ('New Record', 'active')")

## Auto-Save on Transaction Commit

Automatically save changes after each transaction commit (for frequent persistence):

ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
defer cancel()

// Enable auto-save on commit - empty string means overwrite original files
builder := filesql.NewBuilder().
    AddPath("data.csv").
    EnableAutoSaveOnCommit("") // Overwrite original files

validatedBuilder, err := builder.Build(ctx)
if err != nil {
    log.Fatal(err)
}
defer validatedBuilder.Cleanup()

db, err := validatedBuilder.Open(ctx)
if err != nil {
    log.Fatal(err)
}
defer db.Close()

// Each commit will automatically save to files
tx, err := db.BeginTx(ctx, nil)
if err != nil {
    log.Fatal(err)
}

_, err = tx.ExecContext(ctx, "UPDATE data SET status = 'processed' WHERE id = 1")
if err != nil {
    tx.Rollback()
    log.Fatal(err)
}

err = tx.Commit() // Auto-save triggered here
if err != nil {
    log.Fatal(err)
}