Set up project scaffolding: GitHub Actions workflows, issue templates, changelog, contributing guidelines, MIT license, and README

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,30 @@
+---
+name: Bug
+about: Report a bug
+title: '[Bug] '
+labels: bug
+assignees: ''
+---
+
+**Description**
+Briefly: what is the problem?
+
+**Steps to reproduce**
+1. …
+2. …
+
+**Expected**
+What should happen?
+
+**Actual**
+What happens instead?
+
+**Environment**
+- OS:
+- Java version:
+- Terminal (e.g. PowerShell, CMD, IDE):
+
+**Optional: code snippet**
+```java
+// minimal example
+```