feat(nextcloud): add Nextcloud-compatible API layer

Implement a complete Nextcloud client compatibility layer so that
Nextcloud desktop/mobile sync clients can connect to OxiCloud.

Key additions:
- Login Flow v2 (device auth) with OIDC bridge support
- WebDAV handler compatible with Nextcloud clients (PROPFIND, GET,
  PUT, DELETE, MKCOL, MOVE, COPY, HEAD, PROPPATCH)
- OCS API endpoints (user info, capabilities, notifications stubs,
  sharees, unified search)
- Basic Auth middleware with app password verification, account
  lockout integration, and blake3-keyed auth cache
- App password management: create, list, revoke via both native
  API (JWT-authenticated profile page) and Nextcloud OCS endpoints
- Nextcloud file ID mapping (oc:fileid) with persistent DB storage
- Chunked upload support (Nextcloud v2 chunking protocol)
- Trashbin WebDAV interface
- Avatar (SVG placeholder) and preview (redirect) handlers
- User profile page with app password management UI
- URL user validation on all DAV routes (403 on mismatch)
- Database schema for app_passwords and nextcloud_object_ids tables

All services are behind a `nextcloud.enabled` config flag and
cleanly separated under src/interfaces/nextcloud/.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/application/services/favorites_service.rs

@@ -1,11 +1,14 @@
+use std::collections::HashSet;
+use std::sync::Arc;
+
+use tracing::info;
+
 use crate::application::dtos::favorites_dto::{
     BatchFavoritesResult, BatchFavoritesStats, FavoriteItemDto,
 };
 use crate::application::ports::favorites_ports::{FavoritesRepositoryPort, FavoritesUseCase};
 use crate::common::errors::{DomainError, ErrorKind, Result};
 use crate::infrastructure::repositories::pg::FavoritesPgRepository;
-use std::sync::Arc;
-use tracing::info;
 
 /// Implementation of the FavoritesUseCase for managing user favorites.
 ///
@@ -142,4 +145,12 @@ impl FavoritesUseCase for FavoritesService {
             favorites,
         })
     }
+
+    async fn batch_check_favorites(
+        &self,
+        user_id: &str,
+        item_ids: &[(&str, &str)],
+    ) -> Result<HashSet<String>> {
+        self.repo.batch_check_favorites(user_id, item_ids).await
+    }
 }