- extractExifData() now async — reads real EXIF tags (Make, Model,
DateTimeOriginal, ISO, FNumber, ExposureTime, FocalLength, GPS)
via exifr.parse() and displays them in the UI
- handlePickedPhoto() + reader.onload made async to support this
- GPS extraction already auto-triggers on photo pick (tryExtractGpsFromPicked)
- Server-side exif_data round-trip already functional (verified)
- DNG/RAW-02: .dng allowed, 20MB limit
