fix(habits): add null check for commit author property

[calilkhalil]

Description

This PR fixes a TypeError that occurs when the GitHub API returns events with commits that don't have an author property defined.

Problem

The habits plugin crashes with the following error:

TypeError: Cannot destructure property 'author' of 'undefined' as it is undefined.
    at file:///metrics/source/plugins/habits/index.mjs:51:21
    at Array.filter (<anonymous>)

This happens because some commits returned by the GitHub Events API don't have the author property (e.g., commits from deleted users, bots, or malformed API responses).

Solution

Added a null check before accessing the author property in the filter callback:

// Before
.filter(({author}) => data.shared["commits.authoring"].filter(...).length)

// After
.filter(commit => commit?.author && data.shared["commits.authoring"].filter(...).length)

Testing

• Tested with a GitHub profile that was previously failing with this error
• The habits plugin now works correctly and gracefully skips commits without author data

Related Issues

Fixes users experiencing "Cannot destructure property 'author' of 'undefined'" errors when using the habits plugin.

[calilkhalil]

Duplicated