refactor(cli): integrate i18n support across commands

- Centralize CLI text strings using the i18n module for localization
- Refactor `createCommand` and `createCli` to improve modularity
- Update logging and error messages to use translated strings

src/cli/main.ts

@@ -1,10 +1,12 @@
 import { Command } from '@cliffy/command';
-import { createCommand } from './create.ts';
 import { getVersion } from '../utils/mod.ts';
+import { t } from '../i18n/mod.ts';
+import { createCommand } from './mod.ts';
 
-await new Command()
-    .name('systemd-timer')
-    .version(await getVersion())
-    .description('CLI Tool zum Erzeugen von systemd .timer und .service Units')
-    .command('create', createCommand)
-    .parse(Deno.args);
+export async function createCli() {
+    return new Command()
+        .name('systemd-timer')
+        .version(await getVersion())
+        .description(t('cli_description'))
+        .command('create', createCommand());
+}