v4.3.9

Summary

• Unified test entry point via nexus-test-runner.js and updated npm test script.
• Cross-platform path identity: samePath in worktree handling, executable resolution improvements, and verification-provider fixes.
• CI hardening: required-jobs gate in the main workflow and clearer plugin-security-scan job naming.
• Expanded tests for worktree paths, test launcher, and verification provider (473 tests).

Test plan

• npm test (473 tests)