[Docs] Make self-hosting setup paths explicit

[roomote-roomote]

​Opened on behalf of @mrubens. View the task or mention @roomote-roomote for follow-up asks.

What changed

• make the self-hosting landing page explicitly treat homelab deployments as self-hosting and route readers by where Roomote will run
• put host, ingress, sign-in, and inference prerequisites before the install command
• define a completed setup as a reachable deployment with working inference and one successful task, not just running containers
• separate Roomote Cloud as the hosted alternative while keeping Railway, Render, server, homelab, VM, and local-development paths distinct

Why this change was made

The existing page mixed hosted and self-hosted paths, placed its setup checklist after the installer, and left the end-to-end success condition unclear. That made it harder for a new homelab operator to choose the right guide and know what needed to be ready before starting.

Impact

Self-hosted operators now get a decision-first path from their intended host to the right guide, see prerequisites before installation, and have a concrete definition of a usable deployment. The deeper homelab and agent-guided installation contracts remain unchanged.

Screenshots

[roomote-community]

1 issue outstanding. See task

• apps/docs/self-hosting.mdx:51 — The prerequisite list incorrectly requires a sign-in provider even though the installer supports first-admin email/password bootstrap.

_{Reviewed e1a4ef3}

[roomote-community]

A sign-in provider is not required before installation: the installer setup link admits the founding admin, who can create an email/password account, and later users can use invite links with email/password. Listing a provider as required makes a valid self-hosted path look blocked until Slack or Microsoft Teams is configured. Make this optional or include email/password bootstrap as the alternative.