Smarter approach to the cookies (#103)

* Smarter approach to the cookies

  - Single maxCookieSize = 1400 constant with clear documentation
  - Combined cookie storage for ~40-45% size reduction
  - Backward compatible migration from legacy cookies

* Tuneup the code.

main_refresh_test.go

@@ -16,12 +16,12 @@ import (
 // TestGetNewTokenWithRefreshToken tests the GetNewTokenWithRefreshToken function
 func TestGetNewTokenWithRefreshToken(t *testing.T) {
 	tests := []struct {
-		name          string
-		refreshToken  string
 		setupMock     func(*httptest.Server) *TraefikOidc
 		validateFunc  func(*testing.T, *TokenResponse, error)
-		wantErr       bool
+		name          string
+		refreshToken  string
 		expectedError string
+		wantErr       bool
 	}{
 		{
 			name:         "successful token refresh",