feat: Separate and persist directory paths for APK selection, export, and settings backup

[Rat-Man-1015]

Feature description:

Currently, the app uses the same file picker location for multiple unrelated actions, including:

• Selecting APK files for patching
• Exporting patched APKs
• Exporting app settings/preferences

This causes all actions to open the same previously used directory instead of maintaining separate, context-specific locations.

Motivation:

At the moment, when selecting a folder in any one workflow (for example choosing an APK for patching), that same directory is later reused when performing completely different actions such as exporting settings or exporting patched APKs.

This creates confusion and unnecessary repetitive navigation.

Example issues:

• APK selection path and export path are shared
• Settings export opens the last used APK selection directory
• Patched APK export also opens the same folder instead of remembering its own location

This leads to:

• Repeated manual folder navigation
• Time loss when switching between workflows
• Mixing unrelated file contexts (APK input vs output vs settings backup)

Desired behavior:

• APK selection should remember its own last-used directory
• Patched APK export should have a separate remembered directory
• Settings/preferences export should also have its own independent directory
• Each workflow should persist its own last-used path independently

This would improve usability by reducing repeated navigation and keeping file operations logically separated by purpose.

[Kuddus73]

I would suggest also when saving:

1. Current keystore
2. Created YouTube icon & header
3. Meged APK
4. Signed APK
5. Created keystore
6. Converted keystore