feat(theme): add top placement for sections

- Add `placement: top|bottom` to the section frontmatter
- Override `DocContent` to render hoisted bands under the page title
- Derive the zebra stripe from list position so split bands stay continuous
- Opt marketing bands out of doc typography with `rp-not-doc`
- Point the legal and privacy contact address at legal@onixbyte.com
- Condense the products pages' body copy into their section frontmatter

theme/components/DocContent.tsx

@@ -0,0 +1,69 @@
+import type { ComponentProps } from "react"
+import { MDXProvider } from "@mdx-js/react"
+import { Content, usePage, useSite } from "@rspress/core/runtime"
+import {
+  Callout,
+  DocContent as OriginalDocContent,
+  FallbackHeading,
+  getCustomMDXComponent,
+  useScrollAfterNav,
+} from "@rspress/core/theme-original"
+import { HomeSections } from "./HomeSections"
+
+/** Taken from upstream so the two cannot drift apart on an Rspress upgrade. */
+type DocContentProps = ComponentProps<typeof OriginalDocContent>
+
+/**
+ * The page title, rendered when the page does not supply an `# h1` of its own.
+ * Mirrors the private `FallbackTitle` inside `@rspress/core`'s `DocContent`.
+ */
+function FallbackTitle() {
+  const { site } = useSite()
+  const { page } = usePage()
+  const { headingTitle, title } = page
+
+  if (site.themeConfig.fallbackHeadingTitle === false || headingTitle) return null
+  return <FallbackHeading level={1} title={title} />
+}
+
+/**
+ * Mirrors `@rspress/core`'s `DocContent`, with one addition: the bands a page
+ * marks `placement: top` render between the page title and the article body.
+ *
+ * Rspress has no slot for that position. `beforeDocContent` sits above the
+ * title, and `afterDocContent` and the `Layout`'s `afterDoc` both sit below the
+ * whole article — which is why sections used to land at the foot of the
+ * products page. Replacing this component is the only way in, so it is a
+ * deliberate copy of upstream and is worth re-diffing whenever Rspress is
+ * upgraded. Everything below comes straight from upstream: `useScrollAfterNav`
+ * restores the scroll position after a client-side navigation, and the MDX
+ * component map is layered as defaults, then the caller's overrides, then the
+ * placeholder the compiled MDX uses for callouts.
+ *
+ * Every page rendering through `DocLayout` goes through here, so be careful:
+ * a mistake affects blogs and project pages as much as the marketing ones.
+ */
+export function DocContent({
+  components,
+  isOverviewPage = false,
+  beforeDocContent,
+  afterDocContent,
+}: DocContentProps) {
+  useScrollAfterNav()
+
+  const mdxComponents = {
+    ...getCustomMDXComponent(),
+    ...components,
+    $$$callout$$$: Callout,
+  }
+
+  return (
+    <MDXProvider components={mdxComponents}>
+      {beforeDocContent}
+      {!isOverviewPage && <FallbackTitle />}
+      <HomeSections placement="top" />
+      <Content />
+      {afterDocContent}
+    </MDXProvider>
+  )
+}