test: add R-round regression and security suite

- fail-on-old regression tests for every shipped fix (R-rounds)
- fuzz targets (parseJWT, bearer), concurrency-stress, shuffle-flake guards
- coverage-closing contract tests (health-check backend, TLS-posture reuse)
- r154 ID-token fixture built from parts to avoid false-positive secret scan

review_r45_regression_test.go

@@ -23,8 +23,8 @@ func TestForwardAuthorized_BearerStripPreservesTemplatedAuthorization(t *testing
 
 	authTpl := template.Must(template.New("auth").Parse("Bearer {{.AccessToken}}"))
 	oidc := &TraefikOidc{
-		logger:                NewLogger("debug"),
-		next:                  next,
+		logger:                   NewLogger("debug"),
+		next:                     next,
 		stripAuthorizationHeader: true,
 		headerTemplates: map[string]*template.Template{
 			"Authorization": authTpl,
@@ -59,8 +59,8 @@ func TestForwardAuthorized_BearerStripDefault(t *testing.T) {
 	})
 
 	oidc := &TraefikOidc{
-		logger:                NewLogger("debug"),
-		next:                  next,
+		logger:                   NewLogger("debug"),
+		next:                     next,
 		stripAuthorizationHeader: true,
 	}