Fix type safety: commentId should be required, not optional

## Problem
The `commentId` field is marked as optional in the interface but is always provided in practice. This is a type safety issue that suggests incomplete refactoring.

## Solution
- If the field is always required in practice, update the interface to reflect this
- Remove optional marker and update all call sites accordingly
- Ensure type definitions match actual usage patterns

## Related
PR #2 review feedback