fix(studio): open a new photo with the GPS stamp off

A photo carrying EXIF GPS arrived with GPS WATERMARK already ON: adoptPhoto
set useGeotag to the presence of the position, so the file's own EXIF decided
to print a location. The stamp is the visitor's to ask for.

A new photo now opens with it OFF whatever the file carries; the position is
still read off the photo and is there the moment the chip is switched on by
hand (and the device-locate try for an EXIF-less frame is unchanged).

Verified in a real Chrome against the built bundle: a GPS photo opens OFF
with no hint, switching the chip ON reads back 'GPS read from the photo.'; a
no-GPS photo opens OFF and offers the manual entry.

docker/frontend/src/App.tsx

@@ -1090,7 +1090,9 @@ export function Workspace() {
       setUndo([def]);
       setRedo([]);
       if (keepGeo) return;
-      setUseGeotag(!!found);
+      // The stamp opens OFF on every new photo, whatever position the file
+      // carries: its own EXIF is not the visitor's choice to print a location.
+      setUseGeotag(false);
       if (!found) setGpsManual({ lat: '', lng: '' });
       // A frame the phone handed over without EXIF gets one automatic try at the
       // device's position, so the GPS stamp is there without a second tap. PRO