Add breastfeeding duration tracking and UI improvements

Features:
- Breastfeeding timer: Click to start, stop to save duration
- Manual duration input: Long-press for NumberPicker (1-60 min)
- Edit breastfeeding duration: Click on duration in event details
- Day separators: Visual dividers between days in event list
- German translations: Added missing strings for puke/bath events,
  time units, amount labels, signature settings, event details

The breastfeeding timer state persists across app restarts.

app/src/main/java/utils/NumericUtils.kt

@@ -79,6 +79,10 @@ class NumericUtils (val context: Context) {
                     LunaEvent.TYPE_WEIGHT -> measurement_unit_weight_base
                     LunaEvent.TYPE_MEDICINE -> measurement_unit_weight_tiny
                     LunaEvent.TYPE_TEMPERATURE -> measurement_unit_temperature_base
+                    LunaEvent.TYPE_BREASTFEEDING_LEFT_NIPPLE,
+                    LunaEvent.TYPE_BREASTFEEDING_BOTH_NIPPLE,
+                    LunaEvent.TYPE_BREASTFEEDING_RIGHT_NIPPLE ->
+                        context.getString(R.string.measurement_unit_time_minutes)
                     else -> ""
                 }
             )