Transcript rendering broken after update — text truncated, markdown not rendered

Description

After a recent update, the Claude Code desktop app transcript view has rendering issues:

1. Text is truncated — messages are cut off mid-sentence, showing partial content
2. Markdown not rendered — code blocks, tables, and formatting appear as raw text or are missing
3. Content overflow — some text appears to overflow its container

Screenshot

The screenshot shows a session where the assistant's response is partially rendered — text is cut off, diff markers (+109 -0) appear inline, and the overall layout is broken.

Environment

• Platform: macOS
• Claude Code version: Latest (updated recently, issue started after update)
• Transcript view mode: Normal
• Language: Mixed English/Traditional Chinese (zh-TW)

Steps to reproduce

1. Open Claude Code desktop app
2. Open any existing session with long conversations
3. Scroll through the transcript — text appears truncated and markdown is not properly rendered

Expected behavior

Full message content should be displayed with proper markdown rendering (tables, code blocks, headings).

Actual behavior

Messages are truncated, markdown is rendered as plain text, and some content appears to overflow containers.