Add HTTP/SSE transport for non-stdio MCP clients

[DoubleH10]

Description

Currently the MCP server only supports stdio transport. Adding HTTP with Server-Sent Events (SSE) would allow web-based MCP clients and remote deployments.

What needs to happen

• Add an HTTP server option (e.g., using uvicorn or starlette)
• Implement SSE transport per the MCP specification
• Add a --transport CLI flag: zatca-mcp --transport sse --port 8080
• Keep stdio as the default for backward compatibility

Helpful context

• Current server entry point: src/zatca_mcp/server.py
• MCP transport docs: https://modelcontextprotocol.io/docs/concepts/transports
• The mcp Python SDK may have built-in SSE support