test: tests unitaires socketio-adapter (8 tests, bun test)

- Injection socket factory pour testabilité (2e param constructeur)
- Tests : état initial, connect, login_error, connect_error,
  reconnecting, reconnexion, logoff, onStateChange
- Script test ajouté dans package.json

package.json

@@ -13,7 +13,8 @@
     "build:linux-x64": "electron-builder --linux --x64",
     "build:linux-arm64": "electron-builder --linux --arm64",
     "dist": "electron-builder",
-    "postinstall": "electron-builder install-app-deps"
+    "postinstall": "electron-builder install-app-deps",
+    "test": "bun test"
   },
   "keywords": [
     "electron",