Fix headless mode: use sleep loop instead of CLI mode (prevent EOF exit)

- Headless now keeps server alive with asyncio.sleep(1) loop
- CLI mode only for non-headless fallback
- Enables running SenSu as daemon/service

config/plugins/commands.yaml

@@ -34,7 +34,7 @@ commands:
     - framework.permission.read
     source: internal
   plugin_status: &id002
-    description: show plugin status
+    description: show status
     permissions: []
     source: plugin.example_plugin
   pm_plugin_status:
@@ -92,7 +92,7 @@ commands:
     permissions:
     - framework.command.test
     source: internal
-last_updated: 252439.598783596
+last_updated: 274185.477575092
 plugin_commands:
   example_plugin:
     echo: *id001