feat: add action

[vaernion]

No description provided.

[Copilot]

Pull Request Overview

This PR transforms a simple no-op action into a functional GitHub Action that detects file changes since the last successful workflow run. The action enables safe continuous deployment by comparing the current commit against the last successful run's commit.

• Replaces echo/output functionality with change detection logic using Git diffs and GitHub API
• Adds workflow history lookup to determine base commit for comparison
• Implements include/exclude path filtering with Git pathspecs

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
action.yml	Complete rewrite from no-op to change detection action with workflow API integration and Git diff logic
README.md	Updated documentation to reflect new action purpose, inputs, outputs, and usage examples
.github/workflows/test.yml	New test workflow demonstrating the action's usage with path filtering

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