experiment with fake cursor pagination approach

[SamMorrowDrums]

Looking at whether making pagination behave more like a cursor would be beneficial or not, in terms of getting agents to natively understand how to get more data, and not naively just get a large result set.

Pinning the number of results, and always providing the next cursor value are key parts of this.

Part of https://github.com/github/github-mcp-server/issues/1362