Explain in detail what open-source dependency vulnerabilities are, including the concept of transitive dependencies. Describe the primary risks and potential impact they pose to software projects and organizations (e.g., data breaches, service disruption, compliance issues, reputational damage).

Describe how modern automated tools, specifically GitHub's Dependabot and npm audit (as an example for the JavaScript ecosystem, though general principles apply), function. Explain their core mechanisms for detecting vulnerabilities (e.g., referencing public vulnerability databases, scanning dependency manifests/lock files) and how they integrate into a typical developer's workflow (e.g., pull requests, CI/CD checks).

Outline a comprehensive modern development workflow for effectively managing open-source dependency vulnerabilities. This should integrate automated scanning, alerting, and patching processes. Include best practices for both proactive (e.g., regular auditing, dependency freshness, policy enforcement) and reactive (e.g., rapid patching, incident response) management strategies. The response should emphasize continuous integration and continuous delivery (CI/CD) integration.