P5 Streams Q+R: TaskAnimations + AnimationTestingScreen

Port iOS TaskAnimations.swift specs (completion checkmark, card transitions,
priority pulse) + AnimationTestingView as dev screen.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

composeApp/src/commonMain/kotlin/com/tt/honeyDue/navigation/Routes.kt

@@ -182,3 +182,8 @@ data class TaskTemplatesBrowserRoute(
     val residenceId: Int,
     val fromOnboarding: Boolean = false,
 )
+
+// Dev-only animation testing screen (P5 Streams Q+R — Android port of
+// iOS AnimationTestingView).
+@Serializable
+object AnimationTestingRoute