[TASK] Fix #658: Generate user.tsconfig for backend module extensions (#819)

In TYPO3 v13, extensions can place User-TSConfig in
Configuration/user.tsconfig for automatic loading (Feature #101807),
replacing the deprecated addUserTSConfig().

- Add generateUserTsConfig() to FileGenerator
- Add Configuration/user.tsconfigt template generating a module.{key}
  block per backend module as a starting point for developers
- Generation is skipped when the extension has no backend modules

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: PKuhlmay

Classes/Service/FileGenerator.php

@@ -172,6 +172,8 @@ public function build(Extension $extension): void
 
         $this->generatePageTsConfig();
 
+        $this->generateUserTsConfig();
+
         $this->generateServicesYaml();
 
         $this->generateBackendModuleFiles();
@@ -289,6 +291,25 @@ protected function generatePageTsConfig(): void
         // when using PLUGIN_TYPE_CONTENT_ELEMENT, so no page.tsconfig generation is needed.
     }
 
+    /**
+     * @throws Exception
+     */
+    protected function generateUserTsConfig(): void
+    {
+        if (!$this->extension->hasBackendModules()) {
+            return;
+        }
+        try {
+            $fileContents = $this->renderTemplate(
+                'Configuration/user.tsconfigt',
+                ['extension' => $this->extension]
+            );
+            $this->writeFile($this->configurationDirectory . 'user.tsconfig', $fileContents);
+        } catch (Exception $e) {
+            throw new Exception('Could not write Configuration/user.tsconfig. Error: ' . $e->getMessage());
+        }
+    }
+
     /**
      * @throws Exception
      */

Resources/Private/CodeTemplates/Extbase/Configuration/user.tsconfigt

@@ -0,0 +1,3 @@
+{namespace k=EBT\ExtensionBuilder\ViewHelpers}<f:for each="{extension.BackendModules}" as="backendModule">module.{extension.extensionKey}_{backendModule.key} {
+}
+</f:for>