✨ Account and auth protobuf and client code

DysonNetwork.Shared/Protos/auth.proto

@@ -0,0 +1,55 @@
+syntax = "proto3";
+
+package dyson_network.sphere.auth;
+
+import "google/protobuf/empty.proto";
+import "google/protobuf/timestamp.proto";
+
+option csharp_namespace = "DysonNetwork.Sphere.Auth.Proto";
+
+service AuthService {
+  // Standard username/password login
+  rpc Login(LoginRequest) returns (LoginResponse);
+
+  // Introspects an OAuth 2.0 access token.
+  rpc IntrospectToken(IntrospectTokenRequest) returns (IntrospectionResponse);
+
+  // Logs out the current session
+  rpc Logout(google.protobuf.Empty) returns (google.protobuf.Empty);
+}
+
+message LoginRequest {
+  string username = 1;
+  string password = 2;
+  // Optional: for 2FA
+  string two_factor_code = 3;
+}
+
+message LoginResponse {
+  string access_token = 1;
+  string refresh_token = 2;
+  int64 expires_in = 3;
+}
+
+message IntrospectTokenRequest {
+  string token = 1;
+  // Optional: token_type_hint can be "access_token" or "refresh_token"
+  string token_type_hint = 2;
+}
+
+message IntrospectionResponse {
+  // Indicates whether or not the token is currently active.
+  bool active = 1;
+  // A JSON string containing the claims of the token.
+  string claims = 2;
+  // The client identifier for the OAuth 2.0 client that requested the token.
+  string client_id = 3;
+  // The username of the resource owner who authorized the token.
+  string username = 4;
+  // The scope of the access token.
+  string scope = 5;
+  // The time at which the token was issued.
+  google.protobuf.Timestamp iat = 6;
+  // The time at which the token expires.
+  google.protobuf.Timestamp exp = 7;
+}