Add JWT Bearer authentication to Swagger setup

Implemented security definitions and requirements for JWT Bearer authentication in the Swagger configuration. This includes defining a "Bearer" security scheme and adding a security requirement to support JWT authorization via the Authorization header.

EnvelopeGenerator.GeneratorAPI/Program.cs

@@ -49,6 +49,31 @@ builder.Services.AddSwaggerGen(options =>
         },
     });
 
+    options.AddSecurityDefinition("Bearer", new OpenApiSecurityScheme
+    {
+        Name = "Authorization",
+        Type = SecuritySchemeType.Http,
+        Scheme = "Bearer",
+        BearerFormat = "JWT",
+        In = ParameterLocation.Header,
+        Description = "JWT-Autorisierungs-Header unter Verwendung des Bearer-Schemas.",
+    });
+
+    options.AddSecurityRequirement(new OpenApiSecurityRequirement
+    {
+        {
+            new OpenApiSecurityScheme
+            {
+                Reference = new OpenApiReference
+                {
+                    Type = ReferenceType.SecurityScheme,
+                    Id = "Bearer"
+                }
+            },
+            new string[] {}
+        }
+    });
+
     var xmlFiles = Directory.GetFiles(AppContext.BaseDirectory, "*.xml");
     foreach (var xmlFile in xmlFiles)
     {