refactor(parser): Use peek_token() to streamline peek operations

[surajk-m]

Closes #830

This PR refactors parser to use peek_token() instead of separate peek() and peek_data() calls.

Changes:

• Replaced instances of peek() / peek_data() call pairs.
• Removed unwrap() by working directly with the peek_token(). This ensures that the token's kind and data are always in sync and that no intermediate changes can occur between the checks.