chore(frontend): refactor navigation and DI setup, remove unused shared module

- Replaced `initKoin` with `startKoin` for DI initialization consistency across platforms.
- Introduced `StateNavigationPort` with `StateFlow` to streamline navigation state management.
- Migrated `AppScreen` to sealed class with route mapping for better navigation handling.
- Deleted unused `frontend/shared` module and removed related dependencies from build files.
- Cleaned up legacy navigation and Redux-related code, aligning with MVVM architecture.

frontend/features/ping-feature/build.gradle.kts

@@ -44,9 +44,6 @@ kotlin {
       // UI Kit (Design System)
       implementation(projects.frontend.core.designSystem)
 
-      // Shared Konfig & Utilities
-      implementation(projects.frontend.shared)
-
       // Generic Delta-Sync core
       implementation(projects.frontend.core.sync)