Markdown links not converted to OSC 8 hyperlinks — trailing ) appended to URL on click

### Describe the bug

When Copilot CLI renders markdown [text](url) links in responses, they are not converted to proper OSC 8 terminal hyperlinks. The raw URL is exposed as plain text,
causing terminal emulators (e.g. WezTerm) to apply their own URL auto-detection — which captures the trailing ) from the markdown syntax as part of the URL. Every clicked link opens the
browser with ) appended, requiring manual correction.

### Affected version

v1.0.5

### Steps to reproduce the behavior

1. Ask Copilot CLI anything that produces a markdown link in the response
2. Observe [text](url) format in the output
3. Ctrl+click the URL in the terminal
4. Browser opens with ) appended — e.g. https://github.com/github/copilot-cli/issues/1813)

### Expected behavior

Markdown [text](url) links should be emitted as OSC 8 terminal hyperlinks — the terminal displays a clean clickable label, the raw ) is never exposed to the terminal's
URL detector.

### Additional context

- OS: Windows 11
- Terminal: WezTerm
- Shell: PowerShell (pwsh)
- Related: #1837 — same root cause (CLI not emitting OSC 8), but scoped to MCP progress messages
- See also: #1818, #1813 — part of a broader rendering pipeline gap pattern in recent versions