Add local Zig std server integration for documentation

[jedisct1]

Implements local documentation serving via zig std command as suggested in #7.

The MCP server now uses the locally installed Zig compiler by default, ensuring documentation always matches the user's actual Zig version.

Fixes #7

[Afirium]

Hey @jedisct1, thank you very much for the implementation!

I tested it and it works almost as expected, here are a few things that need to be changed:

1. Add zig-out/ and package-lock.json to .gitignore (I forgot to do this).
2. Remove zig-out/main.wasm and package-lock.json files from PR.
3. We need to remove the getLocalMainWasm function and always use the wasm module that comes with the package. Because in this case we will get HTML instead of markdown. I initially forked the zig std docs module to return everything in MD format to reduce token usage. This is what the "local" wasm version returns now:

After that, I will merge it and push a new release. Thanks again!

[Afirium]

Great, thanks!