fix: unlisted-recipe share link wrongly warned it wouldn't work (v0.28.3)

The public /r/{id} route allows any visibility except "private", so
unlisted links always worked — the copy-link toast just checked for
visibility === "public" instead of !== "private", flagging unlisted
recipes as broken when they weren't.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "epicure",
-  "version": "0.28.2",
+  "version": "0.28.3",
   "private": true,
   "scripts": {
     "dev": "pnpm --filter web dev",