Fix profile avatar and display name issues

- Increase Dio receiveTimeout to 120s for file uploads
- Reduce WebDAV client timeout to 30s
- Add cache-busting v parameter to avatar URLs
- Add hasChanges logic to disable Save button when no changes made

go_cloud/internal/storage/webdav.go

@@ -42,7 +42,7 @@ func NewWebDAVClient(cfg *config.Config) *WebDAVClient {
 		user:       cfg.NextcloudUser,
 		pass:       cfg.NextcloudPass,
 		basePrefix: strings.TrimRight(base, "/"),
-		httpClient: &http.Client{Timeout: 120 * time.Second},
+		httpClient: &http.Client{Timeout: 30 * time.Second},
 	}
 }