[Integration DoD][MW-08] Add e2e coverage for skills/plugin install lifecycle

[github-actions]

This issue is auto-generated from INTEGRATION_DOD_MAP.md by the nightly DoD gap sync workflow.

Gap

• ID: MW-08
• Owner (area-owner): API

Acceptance Criteria

• E2E tests validate install, uninstall, and rollback behavior with fixture registries.

Verification Commands

bunx vitest run --config vitest.e2e.config.ts test/plugin-install.e2e.test.ts test/skills-marketplace-api.e2e.test.ts test/skills-marketplace-services.e2e.test.ts

Risk

• Runtime install regressions in marketplace/registry flows.

Source

• INTEGRATION_DOD_MAP.md:464

[hellopleasures]

Fix submitted in PR #770.

The "blocks skill without SKILL.md" security-scan test verified the rejection error but did NOT verify the install directory was cleaned up (rollback). The adjacent binary-file and symlink-escape rollback tests both had this cleanup assertion — this was the inconsistent outlier. Added fs.access(installRoot) rejection check to verify directory cleanup.