Retrieve GitHub code scanning and Dependabot alerts via the REST API

Steps

1. Create a GitHub personal access token or GitHub App installation token with the security_events scope (for code scanning) and the dependabot_alerts scope (for Dependabot); use fine-grained tokens scoped to the target repository
2. List code scanning alerts with GET /repos/OWNER/REPO/code-scanning/alerts; filter by state (open, dismissed, fixed), severity, and tool name query parameters
3. Retrieve alert details including the most_recent_instance field which contains the file path, line number, and rule description; use the html_url field to link directly to the alert in the GitHub UI
4. List Dependabot alerts with GET /repos/OWNER/REPO/dependabot/alerts; filter by severity (critical, high, medium, low) and ecosystem; each alert contains a security_vulnerability object with the CVE identifier and affected version range
5. Dismiss alerts programmatically with PATCH requests providing a dismissed_reason and dismissed_comment when a vulnerability is not applicable or has an accepted risk
6. For organization-wide aggregation, use the organization-level endpoints GET /orgs/ORG/code-scanning/alerts and GET /orgs/ORG/dependabot/alerts with appropriate pagination via the Link header