chore: release 2.1.1

2.1.0 was tagged but never published to npm. This release carries the
deep-health 503 handling, the non-idempotent retry guard, and
previous_token_grace_until.

Claude-Session: https://claude.ai/code/session_01Agoc9bRVE9KL7mmWtey9Vq

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@elydora/sdk",
-  "version": "2.1.0",
+  "version": "2.1.1",
   "description": "Node.js/TypeScript SDK for the Elydora tamper-evident audit platform",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",