fix: add Daily Reports to sidebar via get_app_list override

- Create openclaw_daily app (no models, just app config)
- Override get_app_list() in OpenClawAdminSite to inject Daily Reports item
- Use get_app_list approach (not nav-sidebar template override)
- Inject at top of app list for visibility

src/openclaw_daily/apps.py

@@ -0,0 +1,6 @@
+from django.apps import AppConfig
+
+class OpenClawDailyConfig(AppConfig):
+    name = "openclaw_daily"
+    label = "openclaw_daily"
+    verbose_name = "Daily Reports"