release: align the repo version with the shipped 0.2.1 and guard future tags (#219)

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

packages/desktop/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@prismshadow/penguin-desktop",
-  "version": "0.2.0",
+  "version": "0.2.1",
   "private": true,
   "type": "module",
   "description": "PenguinHarness desktop app: Electron shell running @prismshadow/penguin-server as a utilityProcess, window on http://localhost (same-origin HTTP/SSE, no private IPC).",