Fix Sum Sprint duplicate matching and timer layout

[ganesh47]

Summary

• require decorated duplicate-total Sum Sprint cards to match their generated prompt pair
• move the timed countdown ring into the header slot so it no longer overlays the Home button
• update the duplicate-total regression test to cover same-pair success and cross-pair rejection

Refs #1117

Validation

• xcodebuild test -project Mather.xcodeproj -scheme Mather -destination "platform=iOS Simulator,name=iPhone 17,OS=26.5" CODE_SIGNING_ALLOWED=NO on studio: MatherTests completed 292 tests passed.
• The broader run then entered unrelated UI tests and hit simulator/app connection failures in CompactLayoutTests; it was interrupted after the unit suite completed to avoid holding the worker open.
• xcodegen generate on studio could not run because xcodegen was not installed on PATH; this slice did not change project structure.