feat(web): add appearance contrast control - #7906

Bugbot Analysis Progress (5m 21s elapsed)

✅ Gathered PR context (8s)
✅ Completed bug detection (5m 12s)
✅ Posted analysis results (1s)

Final Result: Bugbot completed review - no issues found! ✅

Request ID: serverGenReqId_4de8fda2-0dca-47d5-8e73-cde6f2c577f7