Chat attachment API endpoints

Gram now supports uploading and serving chat attachments through two new API endpoints.

The /rpc/assets.uploadChatAttachment endpoint allows uploading attachments for use in chat conversations. The /rpc/assets.serveChatAttachment endpoint can be accessed with an API key or session cookie. The Gram-Project header is not required on the serve endpoint, making it easy for session-based clients to embed attachments in chat using standard HTML tags.

For example, images can be embedded directly in chat:

<img src="/rpc/assets.serveChatAttachment?id=...&project_id=..." />

Features

• Chat attachment upload and serve endpoints #1173  - Added two new API endpoints for uploading and serving chat attachments, enabling rich media in chat experiences. (Author: @disintegrator )