Run1 scala immutable builder pattern

In distributed systems, objects should be immutable to prevent concurrency issues. The traditional mutable Builder pattern in Java/Python should be adapted to an immutable Builder in Scala using case classes.

Python (Mutable):

class TokenizerBuilder:
    def __init__(self):
        self._tokenizers = []
        
    def add_tokenizer(self, tokenizer):
        self._tokenizers.append(tokenizer)
        return self

Scala (Immutable):

case class TokenizerBuilder(tokenizers: Seq[BaseTokenizer] = Seq.empty) {
  
  // Returns a new builder instance rather than mutating the current one
  def addTokenizer(tokenizer: BaseTokenizer): TokenizerBuilder = {
    this.copy(tokenizers = this.tokenizers :+ tokenizer)
  }

  def build(): UniversalTokenizer = {
    new UniversalTokenizer(tokenizers)
  }
}

// Companion object provides a clean entry point
object TokenizerBuilder {
  def apply(): TokenizerBuilder = new TokenizerBuilder()
}

This guarantees that the builder is thread-safe and can be safely passed across closures in a distributed data pipeline.