- GoogleDriveBackend: list_folder with full pagination, native doc size=None, get_capabilities
- OneDriveBackend: list_folder with @odata.nextLink pagination, get_capabilities
- WebDAVBackend: list_folder via PROPFIND with SSRF re-validation, get_capabilities
- NextcloudBackend: inherits CloudResourceAdapter from WebDAVBackend
- build_cloud_resource_adapter() added to factory
- 22 new contract/behavior/pagination/no-byte-download tests (51 total pass)
cloud.py: list_connections now decrypts and surfaces server_url +
connection_username for nextcloud/webdav providers; folder route uses
{folder_id:path} to handle slashes; translates "root" sentinel to "".
nextcloud_backend.py: skip parent directory entry in PROPFIND Depth:1 results.
webdav_backend.py: add cloud_folder + original_filename params to
upload_object so files land in the user's chosen folder with their real name.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>