fix: drawer category views reset to Home directory after rotation

[thirumani-vihaan]

Description

When the device is rotated, the FragmentStateAdapter aggressively recreates TabFragment, which subsequently calls updatePaths(). In non-FILE modes (like OpenMode.CUSTOM for Images or OpenMode.RECENT for Recent Files), this inadvertently overwrote the database with the Home directory. This PR explicitly overrides onSaveInstanceState in MainFragment to preserve the currentPath and openMode, ensuring the state is correctly restored when the ViewModel is re-initialized post-rotation.

Issue tracker

Fixes #4629

Automatic tests

• Added unit tests for specific individual functions
• Added headless tests for new app functionality
• Added emulator tests for new UI elements

Manual tests

• Done

• Device: Pixel Emulator

• OS: Android 14 (API 34)

Build tasks success

Successfully running following tasks on local:

• ./gradlew assembledebug
• ./gradlew spotlessCheck

Generative code

• This PR used generative code tools (GenAI, LLMs, etc.)

• Model: Gemini 3.1

• Version: 3.1

• Provider: Google DeepMind

[alihrhera]

Consider extracting the saved state restoration into a separate method to keep onCreate() focused and improve readability.

[thirumani-vihaan]

@alihrhera , I extracted the state restoration logic into a separate restoreSavedState method to clean up onCreate. I also swapped out a bulky try/catch block in onSaveInstanceState for a simple null check while I was at it.

Could you please take another look and see if everything looks good?

[alihrhera]

Looks great! I suggest using early returns instead of nested if statements to improve readability. For example:

private void restoreSavedState(Bundle savedInstanceState) {
    if (savedInstanceState == null) {
        return;
    }

    String savedPath = savedInstanceState.getString(KEY_SAVED_CURRENT_PATH);
    if (savedPath != null) {
        mainFragmentViewModel.setCurrentPath(savedPath);
    }

    int savedOpenMode = savedInstanceState.getInt(KEY_SAVED_OPEN_MODE, -1);
    if (savedOpenMode != -1) {
        mainFragmentViewModel.setOpenMode(OpenMode.getOpenMode(savedOpenMode));
    }
}