Preview pane stuck on blank New tab until clicking Open in chat card; reload doesn't fix it

Description

The preview pane (desktop Code tab) sometimes stays on a blank "New tab" screen (generic globe icon, no content) after starting a dev server, instead of navigating to the running server's URL.

Repro steps

1. Start a dev server via a Code session's preview tool (project uses Vite with autoPort: true in .claude/launch.json, so the port differs each run).
2. Pane opens but shows a blank globe icon and "New tab" — never navigates to the server.
3. MCP-level tool calls against the same server (e.g. a DOM/content snapshot tool) succeed and return real page content, confirming the server itself is up and reachable.
4. Reloading inside the pane (refresh icon / ⌘R) does not fix it — stays blank.
5. Clicking "Open" on the server's status card in the chat transcript does fix it — the pane then navigates correctly and renders the app.

Expected

The pane should navigate to the server automatically once it's running, without needing a manual "Open" click from the chat card, especially since reload inside the pane should be equivalent but isn't.

Environment

• macOS 25.6.0 (Darwin)
• Claude Code desktop app
• Dev server: Vite, autoPort: true, port changes on every restart

Notes

This happens consistently on server restarts throughout the day, not just the first start. Screenshots available showing the stuck blank pane vs. the working chat-card "Open" button.