Add navigation link to the Vulnerabilities section of the left navigation menu that allows users to access the Base Images management page.

Requirements:

• Add "Base images" link under Vulnerabilities section in left nav
• Link points to route: /vulnerabilities/base-images
• Navigation item is protected by feature flag: ROX_BASE_IMAGE_MANAGEMENT
• Navigation item respects RBAC permissions (only shown to users with BaseImage read access)

Location:

• Update navigation configuration where Vulnerabilities section is defined
• Position: Below "Workload CVEs" or similar vulnerability-related links

Acceptance Criteria:

• "Base images" link appears in Vulnerabilities section when feature flag is enabled
• Link is hidden when feature flag is disabled
• Link is hidden for users without BaseImage read permissions
• Clicking link navigates to /vulnerabilities/base-images
• Active state highlights when on base images page