fix(storage): avoid invalid MediaStore URI on overwrite save

[sjug]

Type of change(s)

• Bug fix
• Feature / enhancement
• Infrastructure / tooling (CI, build, deps, tests)
• Documentation

What changed and why

• Updates Gallery to use commons 7.0.0, which includes safe MediaStore URI resolution for scoped-storage operations.
• Changes overwrite-save permission handling to request Android 11+ scoped-storage write grants only when the target file already exists.
• Resolves the target file through MediaStore before calling MediaStore.createWriteRequest(...), avoiding invalid URIs like content://media/external/images/media/0.
• Allows new-file save-as paths to proceed without a write request for a non-existent MediaStore item.

This fixes overwrite-save flows such as editing/cropping an image and saving over the original on scoped-storage devices.

Depends on FossifyOrg/commons#339.

Tests performed

• Clean clone of this branch on the Android build host.
• ./gradlew :app:assembleFossDebug
• Installed the debug APK on an Android 16 Pixel device.
• Runtime-tested the crop overwrite-save flow; save succeeds without Invalid Uri: content://media/external/images/media/0.

Before & after preview

N/A — no UI changes.

Closes the following issue(s)

• Closes Illegal argument exception when cropping #1031

Checklist

• I read the contribution guidelines.
• I manually tested my changes on device/emulator (if applicable).
• I updated the "Unreleased" section in CHANGELOG.md (if applicable).
• I have self-reviewed my pull request (no typos, formatting errors, etc.).
• I understand every change in this pull request.