restructure backend

src/api.ts

@@ -0,0 +1,18 @@
+export async function getImage(req: Bun.BunRequest<"/api/cards/:id">) {
+    const { id } = req.params;
+    let file = Bun.file(`images/cards/${id}.png`);
+    let type = "png";
+
+    if (!(await file.exists())) {
+        file = Bun.file(`images/cards/${id}.jpg`);
+        type = "jpg";
+
+        if (!(await file.exists())) {
+            file = Bun.file("images/cards/placeholder.png");
+            type = "png";
+            console.error(`File for image ${id} does not exist, serving placeholder`);
+        }
+    }
+
+    return new Response(file, { headers: { "Content-Type": `image/${type}` }, status: 200 });
+}