Feature: Add data-author attribute to blame gutter for CSS styling

[ajanderson1]

Feature Request

Add a data-author attribute to the .obs-git-blame-gutter elements containing the commit author name/email. This would enable users to style blame lines differently per author using CSS snippets.

Use Case

When collaborating with others (or with AI assistants like Claude that commit with a distinct author identity), it's helpful to visually distinguish who wrote each line at a glance. Currently, the line authoring feature supports:

• Age-based color gradient (colorNew/colorOld)
• Single text color via --obs-git-gutter-text

But there's no way to style lines differently based on who wrote them.

Proposed Solution

When rendering the blame gutter, add a data attribute with the author:

<!-- Current -->
<div class="cm-gutterElement obs-git-blame-gutter">
  <div>Claude  2 days ago</div>
</div>

<!-- Proposed -->
<div class="cm-gutterElement obs-git-blame-gutter" data-author="Claude" data-author-email="claude@anthropic.local">
  <div>Claude  2 days ago</div>
</div>

This would allow CSS like:

.obs-git-blame-gutter[data-author*="Claude"] {
    --obs-git-gutter-text: #ff9500;
    background-color: rgba(255, 149, 0, 0.1);
    border-left: 2px solid #ff9500;
}

.obs-git-blame-gutter[data-author*="MyName"] {
    --obs-git-gutter-text: #4a9eff;
    background-color: rgba(74, 158, 255, 0.1);
    border-left: 2px solid #4a9eff;
}

Alternatives Considered

• CSS text matching: Not possible - CSS cannot select based on text content
• Custom plugin with MutationObserver: Works but adds overhead and complexity
• Age-based coloring only: Doesn't distinguish collaborators

Additional Context

The implementation in lineAuthorProvider.ts already has access to the author information when rendering - this would just require passing it through as a data attribute on the DOM element.

Thank you for the excellent plugin!