v0.4.0

Fixed

• Fixed compilation error in OpenTelemetryMiddleware where lambda returned a value from void method
• Fixed silent exception swallowing in OJSWorker heartbeat loop — errors are now logged
• Fixed DRY violation in HttpTransport by extracting shared request logic into doRequest()
• Fixed OJSTesting thread-safety: replaced volatile singleton with ThreadLocal for safe parallel test execution
• Fixed silent exception swallowing in OJSWorker.nackJob() — errors are now logged at DEBUG level

Changed

• Extracted HttpTransport.Json nested class to top-level org.openjobspec.ojs.transport.Json for better modularity
• Decoupled OJSTesting from OJSClient — OJSClient no longer imports or references OJSTesting
• OJSTesting.client() and OJSTesting.transport() provide a FakeTransport-backed client for tests

Added

• OJSClient implements AutoCloseable — enables try-with-resources for proper async executor shutdown
• module-info.java for JPMS support — exports org.openjobspec.ojs, org.openjobspec.ojs.transport, org.openjobspec.ojs.testing
• Input validation using OJSError.ValidationError for blank job types in JobRequest and OJSWorker.register()
• JaCoCo coverage badge in README and CI workflow
• JSON parser safety limits: max depth (128) and max input length (10 MB) to prevent stack overflow and OOM
• Unit tests for OpenTelemetryMiddleware (0% → 100% coverage)
• Unit tests for OJSTesting assertions and utilities (53% → 100% coverage)
• Unit tests for OJSClient.Builder retry and transport options (52% → 100% coverage)
• OJSTesting fake mode integration with OJSClient — OJSTesting.fake() now intercepts enqueue calls
• Platform logging (System.Logger) throughout OJSWorker for start/stop, job processing, and errors
• CONTRIBUTING.md with build instructions and contribution guidelines
• CODE_OF_CONDUCT.md (Contributor Covenant v2.1)
• SECURITY.md with vulnerability reporting policy
• CHANGELOG.md (this file)
• GitHub issue templates (bug report, feature request)
• GitHub pull request template
• Dependabot configuration for Maven dependency updates