Remove expect/actual and switch to Koin for dependency injection

[ShadAdman]

Description

Refactor the project to remove the usage of expect/actual for dependency management and adopt Koin as the dependency injection framework throughout the codebase. Using Koin will simplify the shared code and improve maintainability across platforms.

Tasks

• Remove all expect and actual declarations related to dependency management.
• Integrate Koin into the shared module(s) and set up dependency modules for each platform.
• Refactor code to use Koin injection where platform-specific implementations were previously provided via expect/actual.
• Update documentation and relevant build scripts if needed.

Acceptance Criteria

• No remaining expect/actual dependency injections for common functionality.
• Koin is the DI method across platforms.
• All tests pass.