fix(timer): always show H:MM once the timer reaches 60 minutes

[Xitee1]

Summary

• A full hour was rendered as a bare 1 with a small "hour" label, which reads like "1 minute" at a glance.
• From 60 minutes on the dial display now always uses the H:MM form with the hr · min label: 60 minutes shows as 1:00, 120 minutes as 2:00, 90 minutes stays 1:30.
• Below 60 minutes nothing changes (45 / "minutes").
• The now-unused time_unit_hour / time_unit_hours strings are removed in both values/ and values-de/.

Only TimeDisplay.kt was affected: the notification uses the notification_minutes_remaining plural and the widget shows plain minutes, so neither had the hour-only form.

Test plan

• ./gradlew :feature:timer:lintDebug passes
• Set the dial to exactly 60 min → shows 1:00 / HR · MIN
• Set the dial to 120 min → shows 2:00 / HR · MIN
• Set the dial to 90 min → shows 1:30 / HR · MIN
• Set the dial to 45 min → still shows 45 / MINUTES

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