This commit introduces a new GitHub Actions workflow for performance benchmarking. The workflow is triggered on `pull_request_target` events and can be triggered with a "/rerun-benchmarks" comment in the PR. It should be compatible with PRs from both forks and the main repository. It includes steps for setting up the environment, checking out the PR and main branches, installing dependencies, and running benchmarks on both branches. The results are then compared, encoded, and posted as a comment on the PR.