Integrate secret parameter into peer classes

- Add secret field to PeerOptions interface
- Pass secret when creating offers in CreatingOfferState
- Pass secret when answering offers in AnsweringState
- Bump version to 0.7.7

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "@xtr-dev/rondevu-client",
-  "version": "0.7.6",
+  "version": "0.7.7",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@xtr-dev/rondevu-client",
-      "version": "0.7.6",
+      "version": "0.7.7",
       "license": "MIT",
       "dependencies": {
         "@xtr-dev/rondevu-client": "^0.5.1"