feat(website): add the project site and deploy it to GitHub Pages

A Vite + React + TypeScript + Tailwind v4 site under website/, built from
the soulseek-rs design system so the site and the TUI stay one product.
The colour tokens in src/index.css are the same values as
soulseek-rs/src/ui/styles.rs; change one, change both.

The hero is a working recreation of the TUI: it plays one scripted run and
then takes the keyboard, or lands on the resting state directly under
prefers-reduced-motion. Its sample data is invented or public domain, per
the tone-of-voice guardrail against naming copyrighted material.

Static output rather than an SPA shell. `bun run build` compiles the client,
compiles the same app for Node, then renders every route in src/lib/routes.ts
to its own file with that route's title, description and canonical URL. A
direct link to /install therefore answers 200 with real markup instead of
GitHub's 404 page. routes.ts is keyed into App.tsx by literal path, so adding
one without the other fails typecheck rather than shipping a page whose body
says "not found" under the right title.

Theme is resolved once by an inline script before first paint and adopted by
React through useSyncExternalStore, so there is no flash and no hydration
mismatch on the toggle. Light mode re-cuts the semantic hues darker: phosphor
and tape read on vinyl but wash out on manila.

CI and release skip website-only pushes, and Pages skips Rust-only ones. The
two Rust workflows share one paths-ignore list so they can only skip
together, which keeps the release ci-gate from polling for a run that was
never queued. That gate also now treats a cancelled CI as "keep waiting"
rather than a failure, since cancel-in-progress cancels the older SHA on
every back-to-back push.

website/index.html

@@ -0,0 +1,63 @@
+<!doctype html>
+<html lang="en" data-theme="dark">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1" />
+    <!-- Root-relative on purpose: Vite rewrites this against `base`, so the
+         deploy path lives in vite.config.ts alone. -->
+    <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
+
+    <title>soulseek-rs, a Soulseek client for your terminal</title>
+    <meta
+      name="description"
+      content="soulseek-rs is a keyboard-driven Soulseek client and a Rust protocol library. Search, share, browse, and chat from your terminal."
+    />
+    <!-- Browser chrome follows the theme; one value would be wrong half the time. -->
+    <meta name="theme-color" content="#14110F" media="(prefers-color-scheme: dark)" />
+    <meta name="theme-color" content="#F2EDE4" media="(prefers-color-scheme: light)" />
+
+    <meta property="og:type" content="website" />
+    <meta property="og:title" content="soulseek-rs" />
+    <meta
+      property="og:description"
+      content="A Soulseek client and protocol library for Rust. Search, share, browse, and chat from your terminal."
+    />
+    <!-- og:url and canonical are rewritten per route by scripts/prerender.ts. -->
+    <meta property="og:url" content="https://michel.github.io/soulseek-rs/" />
+    <link rel="canonical" href="https://michel.github.io/soulseek-rs/" />
+    <meta name="twitter:card" content="summary" />
+
+    <!-- IBM Plex Mono is the brand typeface. CDN rather than self-hosted
+         binaries, matching the design system's tokens/fonts.css. OFL 1.1. -->
+    <link rel="preconnect" href="https://fonts.googleapis.com" />
+    <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin />
+    <link
+      rel="stylesheet"
+      href="https://fonts.googleapis.com/css2?family=IBM+Plex+Mono:wght@400;500;700&display=swap"
+    />
+
+    <script>
+      // Runs before first paint so the right theme is already on <html>.
+      // Without it the page flashes the wrong background on every load.
+      // Mirrors the resolution order in src/theme/theme-provider.tsx.
+      ;(function () {
+        try {
+          var stored = localStorage.getItem('ssrs-theme')
+          var dark =
+            stored === 'dark' ||
+            ((stored === null || stored === 'system') &&
+              window.matchMedia('(prefers-color-scheme: dark)').matches)
+          var theme = dark ? 'dark' : 'light'
+          document.documentElement.dataset.theme = theme
+          document.documentElement.style.colorScheme = theme
+        } catch (e) {
+          // localStorage blocked; the dark default in the markup stands.
+        }
+      })()
+    </script>
+  </head>
+  <body>
+    <div id="root"></div>
+    <script type="module" src="/src/main.tsx"></script>
+  </body>
+</html>