Add Tag-Based Categorization / Filtering

[victorwwd]

Description

Git Graph currently filters and groups commits based on branches only.
In repositories that use tags heavily (e.g. release tags, version tags), it would be very useful to also group and filter by tags.

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Suggested UI / Behavior

Extend the existing branch structure to include tags, for example:

branches
├─ main
├─ develop
└─ tags
   ├─ v1.0.0
   ├─ v1.1.0

Or conceptually:

branches → branches / tags

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Why This Helps

• Easier navigation of release commits
• Clear separation between mutable branches and immutable tags
• Better usability in repositories with many tags

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Compatibility

This could be optional (configurable) and would not affect existing branch-only workflows.

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