New: take a photo directly when scanning a deck

Adding a deck to TCGCore now supports snapping a photo straight from your phone's camera, instead of only being able to pick an existing picture from your gallery. On the Add a deck page, in both the regular deck flow and the limited-deck (draft/sealed) flow, you'll now see two buttons: "Take photo" opens your camera directly, and "Choose photo" still works the same way as before, letting you pick an image you already have saved. There's also a short tip above the buttons now: fit your whole deck into one photo, and make sure the card names are readable. You don't need to get the full cards in frame, just the titles.