Zenos yae Galvus

> Yes...the coming days promise to be most interesting. Most interesting.

Headline changes:

- ed25519 signing keys for Anubis can be stored in the flag
  `--ed25519-private-key-hex` or envvar
  `ED25519_PRIVATE_KEY_HEX`
- Add the ability to set the cookie domain with the envvar
  `COOKIE_DOMAIN=techaro.lol` for all domains under `techaro.lol`
- Add the ability to set the cookie partitioned flag with the envvar
  `COOKIE_PARTITIONED=true`

Many other small changes were made, including but not limited to:

- Fixed and clarified installation instructions
- Introduced integration tests using Playwright
- Refactor & Split up Anubis into cmd and lib.go
- Fixed bot check to only apply if address range matches
- Fix default difficulty setting that was broken in a refactor
- Linting fixes
- Make dark mode diff lines readable in the documentation
- Fix CI based browser smoke test

Users running Anubis' test suite may run into issues with the integration tests
on Windows hosts. This is a known issue and will be fixed at some point in the
future. In the meantime, use the Windows Subsystem for Linux (WSL).
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qfBdnj8B7ruMg7R4UAAAADZ2l0AAAAAAAAAAZzaGE1MTIAAABTAAAAC3NzaC1lZDI1NTE5
AAAAQJ6tRmGzgfOWkb4rm9ifs3z4IORQJaUtiUoT3BnWvllGl6oxsq1a1LqbPc3GhlO2MP
yi9Bn4hehBYN/AiA0lYwc=
-----END SSH SIGNATURE-----