Converting RAW to HEIC inside Apple Photos: App Intents, HDR gain maps, and never losing a metadata field

Short summary

Building RawToHEIC required choosing App Intents over Share Extensions to access full Photos library permissions for asset deletion. The real challenge was preserving metadata (albums, favorites, EXIF, GPS, creation date) through encode-time handling, not post-processing. Safety was critical: never delete originals before HEIC verification, batch deletions atomically, and fail gracefully to prevent orphaned photos.

• •App Intents provide full app permissions vs Share Extensions' sandbox—essential for library mutations like deletion
• •Metadata preservation requires encode-time handling, not patching EXIF afterward—design choice prevents silent failures
• •Safety invariants prevent data loss: verify conversions before deletion, batch deletes atomically, graceful degradation on failures

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