[Bug] /mcp dialog no longer shows claude.ai MCP marketplace list (v2.1.140)

Environment

• Claude Code version: 2.1.140
• OS: macOS 14.7.1 (Sonoma)
• Auth method: claude.ai (Max subscription)
• Install: cmux desktop app + ~/.local/bin/claude (both affected)

Description

The /mcp dialog no longer shows the claude.ai-provided MCP server browse/marketplace list. The list was previously visible but has disappeared.

Steps to Reproduce

1. Open Claude Code (terminal or cmux desktop app)
2. Type /mcp
3. The dialog opens but the claude.ai MCP marketplace/recommended server list is absent

Expected Behavior

A browseable list of available MCP servers provided by claude.ai should appear in the /mcp dialog, allowing users to discover and install MCP servers.

Actual Behavior

The marketplace list is completely absent. Only currently configured MCP servers (or empty state) is shown.

Attempted Fixes

• claude logout && claude login — no change
• Tested in both cmux desktop app and raw terminal claude binary — same result
• No relevant blocking settings in ~/.claude/settings.json (mcpServers: {}, extraKnownMarketplaces only adds openai-codex)

Additional Notes

Similar to #18250 (marketplace not visible after v2.1.7) but occurring in v2.1.140.