Rich text messages: portrait images/videos render inside oversized square media frames #244

Bug

Tall portrait media embedded in a Rich Text Message (InstantPage V2) can appear inside an approximately square layout frame with substantial side padding/background, rather than in a tight frame preserving the media's intrinsic aspect ratio.

This differs noticeably from ordinary Telegram photo/video messages.

Steps to reproduce

1. Send a Rich Text Message containing a portrait .image or .video block (for example, 1080×2400).
2. Open the message in Telegram for macOS.
3. Compare its media preview with the same media sent as a regular photo/video.

Expected behavior

A preview preserving the media aspect ratio, subject to reasonable maximum dimensions.

Actual behavior

The outer media frame may become approximately square, with the portrait content letterboxed on both sides.

Root cause analysis

The relevant implementation is in two files:

1. packages/ChatUI/Sources/ChatUI/ChatRichTextRowItem.swift

Rich text messages are rendered using layoutInstantPageV2() with fitToWidth: true and mediaBleed parameters.

2. packages/InstantPageUI/Sources/InstantPageUI/InstantPageV2Layout.swift

Both .image and .video blocks are processed