Why: Plugin pages must mount through a host bridge, and button versus chat command parity needs a check that vitest does not execute as a unit test.
Evidence: npx vitest run passed. The Playwright file lives under e2e and is outside the tsconfig include.
Impact: loadPluginPage expects mount/unmount. @playwright/test is not a required dependency yet.
Refs: docs/proposals/2026-10-01-plugin-contract-v2.md
Co-authored-by: Cursor <cursoragent@cursor.com>
