build(uhr): alarms, ringing, timer, stopwatch, world clock, bedtime, settings, widgets

- exact alarms via setAlarmClock, rescheduled on boot/time/zone change and app update
- foreground ringing service: alarm-stream audio with gradual volume, vibration,
  full-screen screen with slide to snooze/stop, silence-after, missed notification
- timers and stopwatch keep timestamps only; live countdown/chronometer notifications
- world clock offline from the time zone database (no network permission at all)
- own alarm tone, own analog face and launcher icon
- next-ring logic unit-tested incl. DST gaps and zone changes; screenshot tests

Co-Authored-By: Claude Opus 5.5 <[email protected]>

uhr/build.gradle.kts

@@ -0,0 +1,7 @@
+plugins {
+    id("com.android.application") version "8.13.0" apply false
+    id("org.jetbrains.kotlin.android") version "2.2.20" apply false
+    id("org.jetbrains.kotlin.plugin.compose") version "2.2.20" apply false
+    id("com.google.devtools.ksp") version "2.2.20-2.0.3" apply false
+    id("io.github.takahirom.roborazzi") version "1.46.1" apply false
+}