<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
- **New Features**
- Safer, consistent file downloads with automatic attachment headers and
filenames.
- Smarter MIME detection for uploads (avatars, workspace blobs, Copilot
files/transcripts).
- Sensible default buffer limit when reading uploads.
- **Bug Fixes**
- Prevents risky content from rendering inline by forcing downloads and
adding no‑sniff protection.
- More accurate content types when original metadata is missing or
incorrect.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
close CLOUD-227
close CLOUD-230
#### PR Dependency Tree
* **PR #12761** 👈
* **PR #12924**
* **PR #12925**
This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **New Features**
* Introduced a comprehensive commenting system, enabling users to
create, update, resolve, and delete comments and replies on documents.
* Added support for uploading attachments to comments, with clear error
messaging if size limits are exceeded.
* Implemented role-based permissions for comment actions, including a
new "Commenter" role.
* Enabled paginated listing and change tracking of comments and replies
via GraphQL queries.
* Provided full localization and error handling for comment-related
actions.
* **Bug Fixes**
* Improved uniqueness handling when fetching user data for comments and
replies.
* **Documentation**
* Extended GraphQL schema and frontend localization to document and
support new comment features.
* **Tests**
* Added extensive backend test suites covering all comment and reply
functionalities, permissions, and attachment uploads.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
DarkSky