[Bug]: MCP servers from global config (~/.config/opencode/opencode.json) are ignored

[nguyenngothuong]

Bug Description

The listMcp() function in packages/server/src/mcp.ts only reads MCP configurations from the workspace-level opencode.json(c), completely ignoring global MCP servers configured in ~/.config/opencode/opencode.json.

This forces users to duplicate their global MCP configurations in every workspace, which is error-prone and inconvenient.

Steps to Reproduce

1. Configure MCP servers in the global config:

   // ~/.config/opencode/opencode.json
   {
     "mcp": {
       "my-server": {
         "type": "local",
         "command": "npx",
         "args": ["-y", "@modelcontextprotocol/server-filesystem", "/tmp"]
       }
     }
   }

2. Open a workspace that has no workspace-level opencode.json

3. Open the MCP panel in OpenWork

Expected: my-server appears in the MCP list
Actual: MCP panel is empty

Root Cause

listMcp() in packages/server/src/mcp.ts reads only:

const { data: config } = await readJsoncFile(opencodeConfigPath(workspaceRoot), ...);

There is no fallback to the global config at ~/.config/opencode/opencode.json.

Expected Behaviour

Global MCPs should be merged with project MCPs. Project-level entries take precedence over global ones (same name → project wins). Each item should carry the correct source field ("config.global" vs "config.project") so the UI can distinguish them.