chore: cleanup

[AlejandroFabianCampos]

Cleanup

• Import examples, generated docs, import error messages and client test fixtures used endpoint ids and subdomains from a real account. They now use placeholders: 123456, 123457 and example-name.<network>.quiknode.pro. The fixtures keep their URL shapes (the /evm suffix, the trailing slash), so the redaction tests exercise the same cases.
• The changelog notes read as changes to earlier behaviour. They now describe how the first release works.

make test, make lint and make docs pass.