fix(workshop): use shared dayjs formatting

apps/docs/src/components/store/store-utils.ts

@@ -0,0 +1,16 @@
+import type { StoreSubmission } from "@site/src/lib/pocketbase";
+
+export const downloadSubmissionJson = (submission: StoreSubmission) => {
+  const url = URL.createObjectURL(new Blob([submission.content], { type: "application/json" }));
+  Object.assign(document.createElement("a"), {
+    href: url,
+    download: `${submission.title.replace(/[^a-z0-9-_]+/gi, "-").toLowerCase()}.json`,
+  }).click();
+  URL.revokeObjectURL(url);
+};
+
+export const voteDelta = (prev: 1 | -1 | undefined, next: 1 | -1): [up: number, down: number] => {
+  if (!prev) return next === 1 ? [1, 0] : [0, 1];
+  if (prev === next) return next === 1 ? [-1, 0] : [0, -1];
+  return next === 1 ? [1, -1] : [-1, 1];
+};