test: critical-flow E2E (import, session lifecycle, turn cycle)

[mads-jm]

E2E scaffold already exists but is empty (corrected 2026-06-27 during spec drafting). app/playwright.config.ts is present (testDir ./e2e/tests), app/e2e/ has pages/ + an empty tests/, @playwright/test is a devDependency, and npm run test:e2e is wired. So this is not "stand up Playwright" — the gap is writing the specs + an Electron-launch harness (the config baseURL points at the Vite dev server).

Flows to cover (see [[mvp-reality-react-quality]])

• Spotify import funnel
• Session lifecycle (setup → active → end)
• Turn-taking cycle
• Playlist CRUD + export
• P2P replication (hardest)

Epic: epic-app-reliability-quality.md. Plan: report-260627-issue-reconciliation.md.