Add 4x6 template

cards_4x6.typ

@@ -0,0 +1,23 @@
+#{
+  set page(width: 6in, height: 4in, margin: 0em)
+
+  import "common.typ"
+
+  let options = json("options.json")
+  let cards = options.cards
+  let args = options.args
+
+  let content_fn = if args.no_content {
+    _ => []
+  } else {
+    import "content/content.typ"
+    content.content
+  }
+
+  for (idx, card) in cards.enumerate() {
+    if idx != 0 {
+      pagebreak()
+    }
+    common.postcard_content(100%, 100%, content_fn, card)
+  }
+}