Fix general settings route and req.user references

- Update frontend settings service to use correct /api/admin/settings/general route
- Fix all req.user to req.admin references in adminSettings.js
- Ensures settings can be saved without authentication errors

backend/src/routes/admin.js

@@ -7,6 +7,7 @@ const archiveRoutes = require('./adminArchives');
 const emailRoutes = require('./adminEmail');
 const settingsRoutes = require('./adminSettings');
 const eventsRoutes = require('./adminEvents');
+const photosRoutes = require('./adminPhotos');
 
 // Mount sub-routers
 router.use('/dashboard', dashboardRoutes);
@@ -14,5 +15,6 @@ router.use('/archives', archiveRoutes);
 router.use('/email', emailRoutes);
 router.use('/settings', settingsRoutes);
 router.use('/events', eventsRoutes);
+router.use('/events', photosRoutes);
 
 module.exports = router;