style: convert camelCase to snake_case across the project

[abc3]

Convert variable naming from camelCase to snake_case

This PR updates variable naming across the project to follow Elixir naming conventions. All camelCase variables/functions have been converted to snake_case format for better consistency with Elixir style guide and community standards.

Changes:

• recoveryId -> recovery_id
• pubKeyHash -> pub_key_hash
• toJacobian -> to_jacobian
• etc.

No functional changes, only style improvements