Add CLI host/port options for HTTP transports and enforce stdio validation

[cccs-eric]

This PR adds --host and --port CLI options to configure network binding when running the MCP server over HTTP-based transports, and prevents invalid usage with stdio. This is particularly useful in Docker based deployments.

It also partially fixes issue #28.

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Note

Low Risk
Small CLI and startup-parameter change with defaults preserving existing behavior; main risk is misconfiguration of network binding for HTTP/SSE deployments.

Overview
Adds --host and --port CLI options to control bind address/port when running the server with --transport http or sse, and wires these through to mcp.run (keeping stateless_http only for http).

Rejects invalid combinations by raising a click.UsageError if --host/--port are provided with --transport stdio, and adds a CLI test to enforce this behavior.

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[cccs-eric]

I’ve noticed that several community members want to run this MCP server in a shared mode, which the current implementation doesn’t support. I believe I’m the third person to open a similar PR, which suggests the broader vision may not be fully clear yet.

After reading @alexsku’s comment, the rationale makes sense to me. Would you consider adding a brief section to the README that articulates the project’s intended deployment model and vision? I’m happy to align with that approach—in fact, I’ve already implemented something similar while adding features I plan to contribute—but clarifying the vision for the community would go a long way.

If this approach isn’t likely to be merged, I’m happy to close the PR to keep the queue clean—please let me know.

[cccs-eric]

Closing this PR in favor of #83.