[Feature]: Add backend API for bulk file and folder operations

[DenizAltunkapan]

Problem

Cloud Page currently handles file and folder actions one item at a time.

This becomes slow and inconvenient when users need to delete, move, or download multiple items. A future frontend multi-select UI needs a backend contract that can process multiple operations safely and report partial failures.

Proposed solution

Add backend endpoints for bulk operations on files and folders.

Scope:

• bulk delete for files and folders
• bulk move/rename into a target folder where applicable
• bulk download can return an archive or create a later follow-up issue if it needs background processing
• return a structured result per item with success or error information
• keep all operations restricted to the authenticated user's root folder

Example scenario: a user selects ten old files and two folders and deletes them in one action. The API should delete what is allowed and report any item that failed.

Acceptance criteria

• A bulk delete endpoint accepts multiple file/folder paths.
• A bulk move endpoint supports moving multiple items into a target folder.
• The response includes per-item success and failure details.
• Invalid paths, missing items, and permission failures do not break the whole response unexpectedly.
• Path traversal and cross-user access are prevented for every item.
• Tests cover full success, partial failure, invalid paths, and mixed file/folder operations.

[IrfanSyed0721]

Hi @DenizAltunkapan, thank you for the suggestions, Issue #92 sounds perfect! Could you please assign #92 to me? I'll get to work on setting up the repository locally tonight. :)

[DenizAltunkapan]

@IrfanSyed0721 i assigned you