fix(infra): use dns name for docker deploy host

[marzipan99]

Summary

• connect the Docker provider through oyasai.io instead of the current public IP literal
• avoid TLS SAN mismatches when the public IP changes, since the server certificate already includes DNS:oyasai.io

Tests

• /nix/var/nix/profiles/default/bin/nix fmt
• git diff --check
• /nix/var/nix/profiles/default/bin/nix flake check -L failed while building existing Node dependency readdirp before CDKTF completed
• /nix/var/nix/profiles/default/bin/nix build .#oyasai-cdktf -L --no-link failed while building existing Node dependency universalify before oyasai-cdktf completed

Notes

• This touches a CODEOWNERS-owned CDKTF file and should require @shunueda approval.

[marzipan99]

@shunueda 良かれと思ってグローバル IPからoyasai.io に変えたけど、TLS証明を毎回修正する方がいい？

[shunueda]

Suggested change

	host: "tcp://oyasai.io:2376",
	host: `tcp://${platformInfra.rootDnsRecord.name}:2376`,

[shunueda]

@shunueda 良かれと思ってグローバル IPからoyasai.io に変えたけど、TLS証明を毎回修正する方がいい？

Discordで話した通り、とりあえず現状維持でいけるか試して、いけたらこれに変更も検討しよう

[shunueda]

おそらくオンプレだとこっちの方がいい。長期的に移行を検討