Add operator environment detail strip

[cbusillo]

Summary

• make product environment pills selectable in the operator overview
• show the selected stable environment context, URLs, and lane action availability
• clear stale config-status rows on product changes and preserve partial status results when one environment fetch fails

Validation

• pnpm --dir frontend validate
• browser smoke: http://127.0.0.1:4196/ui/?fixtures=1 desktop and mobile fixture passes

Refs #153