publish subcommand's `--file` flag not working

[Yuan325]

Describe the bug A clear and concise description of what the bug is.

To Reproduce Steps to reproduce the behavior:

1. place the server.json in .registry/server.json.
2. Run mcp-publisher publish --file .registry/server.json --dry-run
3. Error Error: server.json not found. Run 'mcp-publisher init' to create one

Expected behavior A clear and concise description of what you expected to happen.

Expected dry run to run on the .registry/server.json file.

Logs If applicable, add logs to help explain your problem.

Here's the error message: Error: server.json not found. Run 'mcp-publisher init' to create one

Additional context Add any other context about the problem here.