V1: Add owner-scoped folder pagination (list_folders_by_owner_paginated)
- New method in FolderRepository trait, PG implementation, service & handler
- Prevents IDOR by filtering folder listings to authenticated user
V2: Enforce ownership checks on folder mutations
- rename_folder, move_folder, delete_folder now require caller_id
- Service verifies folder.owner_id == caller_id (returns 404 on mismatch)
- Propagated to folder_handler, batch_handler, batch_operations, webdav_handler
- delete_folder_with_trash upgraded from OptionalAuthUser to AuthUser
- download_folder_zip now checks ownership before streaming
V3: Fix XSS in frontend via DOM APIs
- sharedView.js: innerHTML → createElement + textContent
- contextMenus.js: innerHTML → DOM construction for share dialog
Cleanup: removed unused OptionalAuthUser import, updated all stubs/mocks
Dionisio