Modernize App to Meet Play Store SDK 36 Requirements

Changes

• Updated dependencies to their latest releases.
• Bundled OpenCV:
  • The OpenCV Manager app is deprecated, and downloading APKs from GitHub is likely not compliant with Google Play policies.
• Updated target and compile SDK to 36.
• Introduced MediaStore for handling all image and PDF storage:
  • PDFs on pre-Android Q devices still use raw files.
• Added PermissionX to manage Camera and (on older devices) Storage permissions.
• Removed all absolute file paths and replaced them with Uris:
  • Includes handling edge cases for sharing files with other apps using both file:// and content:// URIs.

Testing

• ✅ Tested on emulators running SDK 25 and SDK 35.
  • ⚠️ Gallery and Settings header UI appears broken on SDK 35 emulator, but I am unable to address it — I have no experience with layouting, and the UI is generated by a third-party library (I think).
• ✅ Installed and tested on a physical device running SDK 33 — UI looks fine, so the issue may be emulator-specific.