fix: preserve preview docs navigation

src/update.rs

@@ -3000,8 +3000,10 @@ mod tests {
 
     #[test]
     fn preview_manifest_reports_update_when_build_id_differs() {
-        let manifest: PreviewManifest = serde_json::from_str(
-            r####"{
+        let (os, arch) = platform_target();
+        let asset_key = format!("{os}-{arch}");
+        let json = format!(
+            r####"{{
                 "channel": "preview",
                 "base_version": "9.9.9",
                 "build_id": "2026-06-02-abcdef123456",
@@ -3009,29 +3011,29 @@ mod tests {
                 "built_at": "2026-06-02T03:00:00Z",
                 "protocol": 77,
                 "notes": "### Fixed\n- One",
-                "assets": {
-                    "linux-x86_64": {
+                "assets": {{
+                    "{asset_key}": {{
                         "url": "https://example.com/herdr-linux-x86_64",
                         "sha256": "deadbeef"
-                    }
-                },
-                "builds": {
-                    "2026-06-02-abcdef123456": {
+                    }}
+                }},
+                "builds": {{
+                    "2026-06-02-abcdef123456": {{
                         "base_version": "9.9.9",
                         "commit": "abcdef1234567890",
                         "built_at": "2026-06-02T03:00:00Z",
                         "protocol": 77,
-                        "assets": {
-                            "linux_x86_64": {
+                        "assets": {{
+                            "{asset_key}": {{
                                 "url": "https://example.com/herdr-linux_x86_64",
                                 "sha256": "deadbeef"
-                            }
-                        }
-                    }
-                }
-            }"####,
-        )
-        .unwrap();
+                            }}
+                        }}
+                    }}
+                }}
+            }}"####
+        );
+        let manifest: PreviewManifest = serde_json::from_str(&json).unwrap();
 
         let release = release_info_from_preview_manifest(&manifest)
             .unwrap()

website/astro.config.mjs

@@ -63,6 +63,7 @@ export default defineConfig({
       ],
       components: {
         Header: './src/components/Header.astro',
+        Sidebar: './src/components/Sidebar.astro',
         SiteTitle: './src/components/SiteTitle.astro',
       },
       customCss: ['./src/styles/starlight.css'],

website/src/components/Sidebar.astro

@@ -0,0 +1,49 @@
+---
+import MobileMenuFooter from 'virtual:starlight/components/MobileMenuFooter';
+import SidebarPersister from '@astrojs/starlight/components/SidebarPersister.astro';
+import SidebarSublist from '@astrojs/starlight/components/SidebarSublist.astro';
+
+const { sidebar } = Astro.locals.starlightRoute;
+const pathname = Astro.url.pathname;
+const isPreview = pathname === '/docs/preview/' || pathname.startsWith('/docs/preview/');
+const channelSidebar = isPreview ? rewriteSidebar(sidebar) : sidebar;
+
+function rewriteSidebar(entries) {
+  return entries.map((entry) => {
+    if (entry.type === 'link') {
+      const href = previewHref(entry.href);
+      return {
+        ...entry,
+        href,
+        isCurrent: samePath(href, pathname),
+      };
+    }
+    const rewrittenEntries = rewriteSidebar(entry.entries);
+    return {
+      ...entry,
+      entries: rewrittenEntries,
+    };
+  });
+}
+
+function previewHref(href) {
+  if (!href.startsWith('/docs/') || href.startsWith('/docs/preview/')) return href;
+  return href === '/docs/' ? '/docs/preview/' : href.replace(/^\/docs\//, '/docs/preview/');
+}
+
+function samePath(left, right) {
+  return stripTrailingSlash(left) === stripTrailingSlash(right);
+}
+
+function stripTrailingSlash(path) {
+  return path.length > 1 ? path.replace(/\/$/, '') : path;
+}
+---
+
+<SidebarPersister>
+  <SidebarSublist sublist={channelSidebar} />
+</SidebarPersister>
+
+<div class="md:sl-hidden">
+  <MobileMenuFooter />
+</div>

website/src/components/SiteTitle.astro

@@ -1,5 +1,7 @@
 ---
 const { siteTitle, siteTitleHref } = Astro.locals.starlightRoute;
+const isPreview = Astro.url.pathname === '/docs/preview/' || Astro.url.pathname.startsWith('/docs/preview/');
+const docsHref = isPreview ? '/docs/preview/' : '/docs/';
 ---
 
 <div class="title-row sl-flex">
@@ -8,7 +10,7 @@ const { siteTitle, siteTitleHref } = Astro.locals.starlightRoute;
     <span translate="no">{siteTitle}</span>
   </a>
   <nav class="title-nav" aria-label="Primary">
-    <a href="/docs/">Docs</a>
+    <a href={docsHref}>Docs</a>
     <a href="/releases/">Releases</a>
     <a href="/blog/">Blog</a>
   </nav>