fixed swagger

Program.cs

@@ -80,17 +80,25 @@ var app = builder.Build();
 
 if (!string.IsNullOrWhiteSpace(settings.RootPath))
 {
-    app.UsePathBase(settings.RootPath);
+    // UsePathBase requires a leading slash; tolerate ROOT_PATH configured without one.
+    var basePath = settings.RootPath.StartsWith('/') ? settings.RootPath : "/" + settings.RootPath;
+    app.UsePathBase(basePath);
 }
 
 app.UseMiddleware<ExceptionHandlingMiddleware>();
 
-app.UseSwagger();
+// Serve the OpenAPI document under the same /docs prefix as the UI so a relative endpoint
+// resolves correctly both locally and behind a reverse-proxy path base (ROOT_PATH).
+app.UseSwagger(options =>
+{
+    options.RouteTemplate = "docs/{documentName}/swagger.json";
+});
 app.UseSwaggerUI(options =>
 {
-    // Serve the interactive docs at /docs (matching the sibling microsoft-365-service).
+    // Interactive docs at /docs (matching the sibling microsoft-365-service).
     options.RoutePrefix = "docs";
-    options.SwaggerEndpoint("/swagger/v1/swagger.json", $"{settings.AppName} v1");
+    // Relative endpoint — resolves to {pathBase}/docs/v1/swagger.json in the browser.
+    options.SwaggerEndpoint("v1/swagger.json", $"{settings.AppName} v1");
     options.DocumentTitle = $"{settings.AppName} – API docs";
 });