A single-file browser application that opens the camera, captures a photo, allows drawing on top of it,
and saves one merged image to the device. No external libraries are used. The saved image is generated
directly from the photo layer plus the drawing layer so it matches the edits shown in the browser.
Preview
Mode: Camera Preview
No camera stream yet.
Use Start Camera to request access to the camera.
Saving behavior: the app creates an off-screen merged canvas from the captured photo and the drawing overlay,
then downloads it as a PNG using standard browser APIs.