chore(release): exit Changesets pre mode (next) so the next version pass cuts the 18.0.0 GA

Written by `pnpm changeset pre exit` (@changesets/cli 3.0.3), committed as the
tool wrote it: `.changeset/pre.json` mode "pre" -> "exit", tag unchanged.

Claude-Session: https://claude.ai/code/session_01FM29ZqLTrnPNXxijioZwMp
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

.changeset/pre.json

@@ -1,4 +1,4 @@
 {
-  "mode": "pre",
+  "mode": "exit",
   "tag": "next"
 }