fix: add hash check to polling fallback and persist sidebar state

- Add content hash check to config watcher polling path to match fsnotify
  behavior, preventing unnecessary restarts when .env is touched but
  content unchanged (Related to #748)
- Change settings sidebar to expanded by default and persist user
  preference using usePersistentSignal (Related to #764)

frontend-modern/src/components/Settings/Settings.tsx

@@ -39,6 +39,7 @@ import { SettingsSectionNav } from './SettingsSectionNav';
 import { SettingsAPI } from '@/api/settings';
 import { NodesAPI } from '@/api/nodes';
 import { UpdatesAPI } from '@/api/updates';
+import { usePersistentSignal } from '@/hooks/usePersistentSignal';
 import { Card } from '@/components/shared/Card';
 import { SectionHeader } from '@/components/shared/SectionHeader';
 import { Toggle } from '@/components/shared/Toggle';
@@ -596,7 +597,7 @@ const Settings: Component<SettingsProps> = (props) => {
   );
 
   const [hasUnsavedChanges, setHasUnsavedChanges] = createSignal(false);
-  const [sidebarCollapsed, setSidebarCollapsed] = createSignal(true);
+  const [sidebarCollapsed, setSidebarCollapsed] = usePersistentSignal('settings-sidebar-collapsed', false);
   const [nodes, setNodes] = createSignal<NodeConfigWithStatus[]>([]);
   const [discoveredNodes, setDiscoveredNodes] = createSignal<DiscoveredServer[]>([]);
   const [showNodeModal, setShowNodeModal] = createSignal(false);

internal/config/watcher.go

@@ -265,8 +265,17 @@ func (cw *ConfigWatcher) pollForChanges() {
 			// Check .env
 			if stat, err := os.Stat(cw.envPath); err == nil {
 				if stat.ModTime().After(cw.lastModTime) {
-					log.Info().Msg("Detected .env file change via polling")
 					cw.lastModTime = stat.ModTime()
+					// Check if content actually changed to prevent restart loops on touch
+					newHash, err := cw.calculateFileHash(cw.envPath)
+					if err == nil {
+						if newHash == cw.lastEnvHash {
+							log.Debug().Msg("Detected .env file touch but content unchanged (polling), skipping reload")
+							continue
+						}
+						cw.lastEnvHash = newHash
+					}
+					log.Info().Msg("Detected .env file change via polling")
 					cw.reloadConfig()
 				}
 			}