Markdown bold/backtick text renders as strikethrough artifacts on Windows Terminal

Description

When Claude Code outputs markdown with bold text or backtick code spans inside bullet points, the rendered text shows Unicode combining strikethrough characters bleeding into adjacent characters. The result is garbled/corrupted text that is difficult to read.

Example

Output like:

- **docs/outreach/email-syncfusion-partnership.md** — Rewritten to remove...
- **publishReportToBold** — Now tries PUT update...
- `scripts/test-new-features.js` — 42 tests covering...

Renders as garbled text with strikethrough artifacts through random characters (see screenshot).

Screenshot

The bold file paths and function names render with combining strikethrough characters bleeding into surrounding text. For example docs/outreach/email-syncfusion-partnership.md appears as U̶o̶c̶s̶/ou̶t̶rea̶c̶h/ema̶i̶l̶-syn̶c̶fusion-p̶a̶r̶t̶ne̶r̶ship.m̶d̶.

Environment

• OS: Windows 11 Pro 10.0.26200
• Terminal: Windows Terminal (Git Bash)
• Claude Code version: Latest (claude-opus-4-6 model)
• Shell: bash (MSYS2/Git Bash)

Steps to Reproduce

1. Run Claude Code on Windows Terminal with Git Bash
2. Ask it to perform a task that produces a summary with bold markdown text in bullet points
3. Observe the rendered output — bold/backtick spans show strikethrough artifacts

Expected Behavior

Bold and backtick markdown should render cleanly without combining character artifacts.

Actual Behavior

Characters within and adjacent to bold/backtick spans are corrupted with Unicode combining strikethrough characters, making the text partially illegible.

Notes

• The issue appears specific to bold (**text**) and backtick (` text `) formatting within bullet point lists
• Regular text and headings render correctly
• This may be related to #34247 (Unicode rendering on Windows) or #26390 (markdown renderer GFM issues)