[feature] Port performance comparison workflow from Casbin (Go) to jCasbin

Please implement the automatic performance benchmark comparison feature for jCasbin, mirroring the mechanism used in the Go version.

**Reference Implementation (Go):**

* **Original PR:** [https://github.com/casbin/casbin/pull/1613](https://github.com/casbin/casbin/pull/1613)
* **Workflow File:** `.github/workflows/performance-pr.yml`

**Target Context (Java):**

* **Benchmark Class:** `src/test/java/org/casbin/jcasbin/main/benchmark/EnforcerBenchmarkTest.java`
* **Build Tool:** Maven

**Requirement:**
Create a GitHub Action workflow (`.github/workflows/performance-pr.yml`) that runs the JMH benchmarks on both the base and head commits of a PR, calculates the performance difference (throughput), and posts the result as a comment on the PR.