Convert to monorepo structure

[Shubhdeep12]

a suggestion -

let's split it into separate packages:

• mcp-server (stdio) – current stdio server for local/IDE use (Cursor, Claude, etc.)
• mcp-core – shared types, helpers, config (errors, logger, etc.)
• mcp-cloudflare – HTTP MCP for hosted use, OAuth, etc.
• mcp-cli – drive the server from the terminal and test flows
• mcp-evals – test tool behaviour and quality

We can set up a pnpm workspace and move the existing code into these packages.

[Shubhdeep12]

Definitely, this can pulled off once #9 is completed.

[Shubhdeep12]

hey @drish any thoughts here?