feat(site): phase 1 — the foundation

Astro 7 with the Node adapter, Starlight mounted at /docs, the token file, both
self-hosted typefaces, the layout shell, and the two build-time checks from §12.

The palette's gold and cyan are sampled from runic-emblem.png rather than
guessed, per §11: 494,059 opaque pixels binned by hue, each value annotated with
its measured contrast against the ground, and restricted rather than brightened
where a ratio fails.

- checkTokens.mjs fails the build on any colour literal outside tokens.css,
  which is what keeps §7's "recolouring is a file copy" promise true.
- checkFacts.mjs re-reads all 14 externally-sourced facts from their authorities
  over the Gitea API and fails on disagreement. It also enforces D13: no email
  address in the source outside brand-default/brand.json.
- Both were negative-tested; neither has ever been allowed to pass by default.

§6 asks for output:'server' with per-page prerender=true. Astro 7 expresses the
same runtime shape as output:'static' with an adapter, opting individual routes
out — so the default is static rather than accidentally server-rendered.

Co-Authored-By: Claude <noreply@anthropic.com>

src/content/docs/docs/index.mdx

@@ -0,0 +1,58 @@
+---
+title: What is Runic Gateway?
+description: An overview of the platform, and where the documentation goes from here.
+---
+
+import platform from '../../../data/platform.json';
+
+Runic Gateway puts a private game server's live state on a public website without ever
+exposing the game to the internet.
+
+The shard dials **out** to a small sidecar over loopback; the sidecar is the only
+network-facing component, and only the website's backend is allowed to talk to it. The
+website degrades gracefully when the game is down, and sensitive events never reach the
+public event stream.
+
+:::note[This documentation is being written in phases]
+The scaffold, theme and sidebar are in place. The pages themselves land in phases 7 and 8,
+starting with the installation path — which is the priority of the whole project, because
+the repositories treat the site and the shard as separate deployments and nothing today
+presents them as one sequence.
+:::
+
+## What the platform is on today
+
+<table>
+  <tbody>
+    <tr><td>Wire protocol</td><td>{platform.protocol}</td></tr>
+    <tr><td>Module API</td><td>{platform.moduleApi}</td></tr>
+    <tr><td>Current bundle</td><td>{platform.bundle.tag}</td></tr>
+    <tr><td>uo-link sidecar</td><td>{platform.releases.link}</td></tr>
+    <tr><td>Plugin overlay</td><td>{platform.bundle.overlay}</td></tr>
+    <tr><td>Installer</td><td>{platform.releases.installer}</td></tr>
+    <tr><td>ServUO (minimum)</td><td>{platform.bundle.servuoMin}</td></tr>
+  </tbody>
+</table>
+
+Every value in that table is read from `src/data/platform.json` and re-checked against its
+source of truth on each build. None of it is typed into prose — including here.
+
+## An install is two installs
+
+Worth stating before anything else, because it is a real trap: a Runic Gateway install is
+two independent deployments.
+
+1. **The site** is a Docker deployment — the website, a database, and a game module.
+2. **The shard side** is the installer binary, run on the game server's host. It sets up
+   the plugin overlay and the sidecar, and it never contacts the website.
+
+They meet at four values pasted into **Admin → Shard**, and at protocol {platform.protocol},
+which both sides check before they will pair.
+
+## Where to go next
+
+The canonical, normative documents live in the
+[`docs` repository](https://gitea.whitlocktech.com/RunicGateway/docs) and always win over
+anything written here. This site authors the *journey* — install, configure, administer,
+extend — which is the thing no existing document owns end to end, because the repositories
+are organised by component and an operator is not.