## Summary
- Add `tabGroups` permission to the extension manifest
- When the connect page opens (via action button click or MCP relay
connect), place it into a green tab group titled "Playwright"
- When a tab is connected to an MCP session, add it to the same group
- When the active connection closes, remove the connected tab from the
group via `chrome.tabs.ungroup`
- Add three tests: group assigned to connect page, group shared with
connected tab, and group cleaned up on disconnect