Bug: /mcp dialog ignores global ~/.claude/.mcp.json when project has no .mcp.json

Bug Description

The /mcp dialog only shows 1 server (plugin:context7:context7) when run from a directory that lacks a project-level .mcp.json, ignoring the global ~/.claude/.mcp.json.

Steps to Reproduce

1. Open Claude Code in a directory without a project .mcp.json (e.g., /c/Users/xchunsk/)
2. Run the /mcp command
3. Only shows "plugin:context7:context7" (1 server)

Expected Behavior

Should show all MCP servers configured in the global ~/.claude/.mcp.json (8 servers in my case).

Actual Behavior

/mcp dialog shows only 1 server. However, claude mcp list from the same directory shows all 8 servers correctly.

Version

2.1.89 (Claude Code)

Additional Context

claude mcp list output (correct):

plugin:context7:context7: ✓ Connected
filesystem: ✓ Connected
context7: ✓ Connected
mariadb: ✓ Connected
playwright: ✓ Connected
sequential-thinking: ✓ Connected
git: ✓ Connected
superpowers: ✓ Connected
apify: ✗ Failed to connect

/mcp dialog output (broken):

1 server
  Built-in MCPs (always available)
❯ plugin:context7:context7 · ✔ connected

The MCP resolution appears to be directory-dependent:

• From ~/.claude/ (where global .mcp.json lives): all 8 servers
• From project folders without their own .mcp.json: fewer servers shown in GUI

This suggests the /mcp dialog is not reading the global config file when no project-level config exists, while the claude mcp list CLI command handles this correctly.