Add Playwright e2e tests for history panel UI interactions #7
Description
Context
Several PR #4 bugs (stale history on article switch, restore-while-saving race) are frontend-only and can't be caught by unit or integration tests. The history panel has interactive state (toggle, lazy-fetch, preview, restore confirmation) that benefits from browser-level testing.
Proposal
Add lightweight Playwright e2e tests covering:
- Expand history panel → versions load
- Switch articles with panel open → history resets (no stale data)
- Select version → preview renders
- Restore flow → confirmation dialog, article reloads
- Restore blocked during autosave
References
public/index.html(history panel,fetchHistory,selectVersion,restoreVersion)- PR feat: version history browser (CE3) #4 review: stale history bug, saving guard bug