Create .tmux files

If `experimental.createTmuxStartupFile` is set in `build.yaml`.

src/Action/CreateListOfFilesToGenerate.php

@@ -146,6 +146,13 @@ final class CreateListOfFilesToGenerate
                 break;
         }
 
+        if (Arr::get($configurationData, 'experimental.createTmuxStartupFile') === true) {
+            $filesToGenerate[] = new TemplateFile(
+                data: 'common/.tmux',
+                name: '.tmux',
+            );
+        }
+
         $filesToGenerate[] = new TemplateFile(
             data: 'common/.githooks/prepare-commit-msg',
             name: 'prepare-commit-msg',

src/Action/GenerateConfigurationFiles.php

@@ -59,6 +59,10 @@ final class GenerateConfigurationFiles
             $this->filesystem->chmod("{$this->outputDir}/.githooks/prepare-commit-msg", 0755);
         }
 
+        if ($this->filesystem->exists("{$this->outputDir}/.tmux")) {
+            $this->filesystem->chmod("{$this->outputDir}/.tmux", 0755);
+        }
+
         if ($this->filesystem->exists("{$this->outputDir}/run")) {
             $this->filesystem->chmod("{$this->outputDir}/run", 0755);
         }

src/DataTransferObject/ConfigDto.php

@@ -116,6 +116,10 @@ final class ConfigDto
                 new Assert\Type('bool'),
             ]),
 
+            'createTmuxStartupFile' => new Assert\Optional([
+                new Assert\Type('bool'),
+            ]),
+
             'runGitHooksBeforePush' => new Assert\Optional([
                 new Assert\Type('bool'),
             ]),