Launch panel: add 'Open in Browser' action for preview configs

Feature Request

When a project has a .claude/launch.json with a preview configuration (e.g., a local dev server), it would be very useful to have an "Open in Browser" button or menu item in the Launch panel (the right-side panel in Claude Code desktop app).

Current behavior

• The Launch panel shows the preview configuration but provides no direct way for the user to open the running server in their browser.
• Users must manually copy/paste URLs like http://localhost:8000 into their browser.
• The panel's 3-dot menu doesn't have a browser launch option.

Desired behavior

• A button or menu item (e.g., "Open in Browser") in the Launch panel that opens the configured URL (e.g., http://localhost:{port}) in the user's default browser.
• This would make it trivial to test web apps being developed with Claude Code.

Use case

Developing a browser-based game (Python WebSocket server + HTML/JS frontend). Frequently need to open http://localhost:8000/player.html and http://localhost:8000/spectator.html for testing. Currently must manually type or bookmark these URLs.

Environment

• Claude Code desktop app on Windows 11
• .claude/launch.json with runtimeExecutable: "python" and port: 8000