fix: use compact in compare method to showcase token savings benefits (v2.x)

[iamgerwin]

Summary

• Changed compare method to use compact() instead of encode()
• Removed $options parameter since compare should always showcase best-case savings
• Ensures TOON's token efficiency is properly demonstrated when using the compare method

Rationale

The compare method is designed to showcase the benefits of using TOON over JSON by comparing token usage. Previously, it accepted an optional $options parameter and used encode(), which meant the comparison could use any format (compact, readable, or tabular).

This change:

• Always uses the compact format, which provides the best token savings
• Simplifies the API by removing the confusing $options parameter
• Ensures a consistent, optimal showcase of TOON's token efficiency

Changes

Modified

• src/Toon.php - Updated compare() method:
  • Removed ?EncodeOptions $options = null parameter
  • Changed $toon = self::encode($value, $options) to $toon = self::compact($value)
  • Updated docblock to clarify that compact format is used

Testing

Run the examples in compact_benefits.php to verify that token savings are properly showcased.

```bash
php compact_benefits.php
```

Branch

This PR targets the main branch (v2.x), which supports PHP 8.1+.