fix: sort contributors alphabetically case-insensitively with login fallback

[vjymisal0]

Description

Fixes #370

Currently, when \contributorsSortAlphabetically: true\ is configured, sorting is performed directly on \�.name\ using default \localeCompare. This leads to:

1. Capitalized names (A-Z) and lowercase names (a-z) sorting into separate clusters rather than a natural, case-insensitive alphabetical sequence.
2. Contributor records that lack an explicit
   ame\ property sorting incorrectly as empty strings instead of falling back to their \login.

Changes Made

• Updated \generateContributorsList\ in src/generate/index.js to sort with \localeCompare(..., undefined, { sensitivity: 'base' })\ with fallback to standard \localeCompare.
• Added fallback to contributor \login\ when
  ame\ is not present, matching the display fallback in src/generate/format-contributor.js.
• Added comprehensive unit tests in src/generate/tests/index.js validating case-insensitive sorting and missing name fallbacks.
• Updated path assertions in src/util/tests/git.js to ensure cross-platform compatibility across Windows, macOS, and Linux.

Testing

• Ran
  pm test\ with 100% tests passing (15 test files, 116 tests).
• Verified ESLint and Prettier formatting checks passed.