Comments in .mcp.json not supported, causing all workspace MCP servers to be skipped

Describe the bug

Repository-level  .mcp.json files are parsed as strict JSON. Adding a  // or  /* ... */  comment causes Copilot CLI to reject the entire file and skip every MCP server it defines.
This makes it difficult to maintain a shared repository configuration containing documentation or temporarily disabled server definitions.

Affected version

1.0.78-0

Steps to reproduce the behavior

1. Create a trusted Git repository.
2. Add .mcp.json:

{
  "mcpServers": {
    // Used for browser-based integration tests.
    "playwright": {
      "type": "stdio",
      "command": "npx",
      "args": ["@playwright/mcp@latest"],
      "tools": ["*"]
    }
  }
}

3. Run copilot mcp list --json
4. Copilot reports:

Warning: skipping workspace MCP config ".mcp.json" because it is malformed:
Invalid JSON: key must be a string

5. Remove the comment and repeat the command. The workspace MCP server is then discovered successfully.

Expected behavior

Copilot CLI should parse .mcp.json as JSONC, supporting  // and  /* ... */ comments while continuing to load valid MCP definitions.

Alternatively, the configuration schema could provide a documented repository-level mechanism such as "enabled": false for retaining optional MCP definitions without loading them.

A malformed individual server entry should ideally not prevent unrelated valid servers from loading.

Additional context

No response