Version 1.1.3: Add image sharing support from other apps

Changes:
- Add ACTION_SEND and ACTION_SEND_MULTIPLE intent filters
- Handle incoming shared images in MainActivity
- Version bump: 1.1.2 -> 1.1.3 (versionCode 16 -> 17)
- Remove promt.md from tracking

Commit: e6555b1537
Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>