feat: add a token handler

ApiDto/Common/OAuthAction.cs

@@ -0,0 +1,17 @@
+namespace Mirea.Api.Dto.Common;
+
+/// <summary>
+/// Defines the actions that can be performed with an OAuth token.
+/// </summary>
+public enum OAuthAction
+{
+    /// <summary>
+    /// The action to log in the user using the provided OAuth token.
+    /// </summary>
+    Login,
+
+    /// <summary>
+    /// The action to bind an OAuth provider to the user's account.
+    /// </summary>
+    Bind
+}