feat(scheduler): add folder_scan_enabled toggle to SchedulerConfig

- Add folder_scan_enabled boolean field (default false) to SchedulerConfig
- Update data/config.json example with new field
- Add checkbox to setup.html and include in JS payload
- Handle field in auth.py setup endpoint
- Expose field in scheduler API response
- Log and return field in scheduler_service.py
- Update docs/CONFIGURATION.md and docs/ARCHITECTURE.md
- Update index.html UI, app.js and scheduler-config.js handlers
- Verified backward compatibility: old configs load with default False

src/server/web/static/js/app.js

@@ -1561,6 +1561,8 @@ class AniWorldApp {
                 document.getElementById('scheduled-rescan-enabled').checked = !!config.enabled;
                 document.getElementById('scheduled-rescan-time').value = config.schedule_time || '03:00';
                 document.getElementById('auto-download-after-rescan').checked = !!config.auto_download_after_rescan;
+                const folderScanEl = document.getElementById('folder-scan-enabled');
+                if (folderScanEl) folderScanEl.checked = !!config.folder_scan_enabled;
 
                 // Update day-of-week checkboxes
                 const days = Array.isArray(config.schedule_days) ? config.schedule_days : ['mon','tue','wed','thu','fri','sat','sun'];
@@ -1603,6 +1605,8 @@ class AniWorldApp {
             const enabled = document.getElementById('scheduled-rescan-enabled').checked;
             const scheduleTime = document.getElementById('scheduled-rescan-time').value || '03:00';
             const autoDownload = document.getElementById('auto-download-after-rescan').checked;
+            const folderScanEl = document.getElementById('folder-scan-enabled');
+            const folderScan = folderScanEl ? folderScanEl.checked : false;
 
             // Collect checked day-of-week values
             const scheduleDays = ['mon','tue','wed','thu','fri','sat','sun']
@@ -1618,7 +1622,8 @@ class AniWorldApp {
                     enabled: enabled,
                     schedule_time: scheduleTime,
                     schedule_days: scheduleDays,
-                    auto_download_after_rescan: autoDownload
+                    auto_download_after_rescan: autoDownload,
+                    folder_scan_enabled: folderScan
                 })
             });