feat(skills): Create a "find first release" skill

[sfreudenthaler]

User Story

As a developer or security professional, I want to be able to find the first release a given issue, PR, or commit appeared in, so that I can quickly identify the impact and deployment of a change.

Acceptance Criteria

• A new skill is created for Gemini, Claude, and Cursor.
• The skill accepts an issue number, pull request URL, or commit SHA as input.
• The skill correctly identifies and outputs the first release (git tag) that contains the specified commit.
• The skill handles cases where the commit is not found or is not part of any release.
• The skill is documented.

Technical Tasks

• Spike: Investigate the most reliable method to traverse git history and identify the first tag associated with a commit. We'll need to see if this is even possible without a full git clone. What if we just git blame the release tags? Just kidding... unless?
• Implement the core logic to find the release from a commit.
• Develop the skill interface for Gemini, Claude, and Cursor.
• Add robust error handling for scenarios where the commit is not found, or no release contains the commit (maybe it's in a feature branch that's still... brewing).
• Create clear documentation for using the new skill.