Ship with landing page which defaults to port 80

[agners]

Now that Home Assistant Core 2026.8.0 defaults to port 80 on HAOS installations we should ship a landing page which defaults to port 80 as well.

Needs home-assistant/landingpage#204.

[sairon]

Everything should be on dev, for RC/stable release we need cli >2026.06.0 and supervisor >2026.07.5 on stable channel (check here before tagging a release).