[Enhancement]: Smooth Material animations and transitions improvements

[MRAKS05]

Problem

The app's UI animations are minimal or non-existent in several areas, making transitions feel abrupt compared to standard Material You design patterns.

Current animation state from codebase

• Onboarding (OnboardingScreen.kt, line 172-177): Uses AnimatedContent with slide transitions — good, but could be smoother
• SettingsScreen: No animations on collapsible Security section or toggle transitions
• DashboardScreen: Stats cards appear statically, no entry animations
• LogsScreen: Log entries have no list item animations
• Screen transitions: No shared element or fade transitions between bottom nav tabs
• OverlayActivity: Countdown timer updates via plain text — no progress animation

Proposed Improvements

Follow Material Motion guidelines (M3) for smooth, responsive animations:

Specific targets

• Bottom nav transitions: Fade/slide content transitions when switching between Dashboard, Exceptions, Logs, Settings
• Collapsible sections: Animated visibility for the Security Settings expand/collapse in SettingsScreen.kt
• List animations: AnimatedVisibility or animateItemPlacement() for LogsScreen entries and Exceptions list items
• Dashboard stats: Count-up animations for "Scanned Today" and "Removed Today" numbers
• Overlay countdown: Circular progress indicator instead of plain text countdown
• Toggle feedback: Ensure Material 3 toggle components use proper motion curves
• Content reveal: Staggered entry animation when screens load

Implementation approach

• Use Compose animation APIs: AnimatedVisibility, animateContentSize, animateXxxAsState, AnimatedContent
• Respect android:animateLayoutChanges equivalent in Compose
• Add Motion easing specs to theme (Theme.kt)
• Keep animations lightweight — avoid jank on lower-end devices
• Respect system "Reduce motion" accessibility setting via LocalAccessibilityManager