Improve Camera2 media selection and preview handling

[rifuki]

Summary

• Resolve selected image/video IDs from DocumentsProvider URIs so media chosen through Android's picker is saved correctly.
• Apply EXIF orientation before passing image sources to native processing.
• Stabilize Camera2 preview replacement by selecting the preview-sized surface, matching blackhole dimensions, and avoiding renderer startup on invalid/abandoned surfaces.
• Compute Camera2 display orientation from sensor/camera facing instead of using raw display rotation.

Issues

• Fixes Image selected from Android picker is not saved #26
• Addresses Camera2 target preview rotates portrait image in Instagram/Facebook #27

Testing

• Built successfully with ./gradlew :app:assembleModernDebug.
• Installed and tested on Sony Xperia XZ3, Android 12, Magisk + LSPosed, Instagram com.instagram.android.
• Verified picker URI media ID resolution with commit 7298162.
• Verified Instagram Instant camera works after the Camera2 surface/session changes.

[rifuki]

screen-20260522-213238.1.mp4