kiegroup/drools — reverse-engineered prompt

Build me a Java based business rules platform for JVM apps. I want developers to be able to define business rules outside normal application code, run those rules quickly and reliably, and use them to make decisions like an expert system would.

It should support a rules engine with forward chaining and backward chaining, DMN decision models, and complex event processing for streams of facts or events. Please include a clean public API, examples that show how to create rules, load them, run a session, and get decisions back, plus tests so I can trust changes later.

Make it feel like a serious open source project, with Maven build support, documentation for getting started, troubleshooting notes for common build issues, and room for extensions like decision tables, persistence, metrics, templates, and integrations with modern Java runtimes.

Look up current docs online if you need to, but keep the first working version focused on the core rule engine and usable examples.