Add configurable formats and lazy decoders, v0.7.1

.env.example

@@ -11,6 +11,9 @@ APP_NAME=Photo Date Editor
 APP_TITLE=Mork Photo Date Editor
 # Optional text shown directly below the page heading.
 APP_SUBTITLE=Family photo metadata editor
+# Enabled groups: jpg, png, tiff, heif, dng
+# Use ENABLED_FORMATS=jpg for a JPEG-only workflow.
+ENABLED_FORMATS=jpg,png,tiff,heif,dng
 MAX_UPLOAD_MB=150
 LOG_LEVEL=INFO
 
@@ -27,4 +30,4 @@ DEFAULT_MAP_LON=11.0
 DEFAULT_MAP_ZOOM=5
 GEOCODER_URL=https://nominatim.openstreetmap.org/search
 # Optional custom identification sent to the geocoder. The default uses APP_NAME, version and APP_URL.
-# GEOCODER_USER_AGENT=MorkPhotoDateEditor/0.7.0 (+https://edit.mork.fyi)
+# GEOCODER_USER_AGENT=MorkPhotoDateEditor/0.7.1 (+https://edit.mork.fyi)