Fix page titles of docs with a notice above the h1

[MattiasBuelens]

Summary

Some pages had the wrong <title>. For example, /millicast/getting-started/ showed "index | Dolby OptiView Documentation" instead of its h1.

Docusaurus sets a doc's title as frontMatter.title ?? contentTitle ?? baseID. It finds contentTitle with parseMarkdownContentTitle (from @docusaurus/utils), a regex that skips leading imports and then expects the # h1 to come next. A component such as <RebrandingNotice /> placed before the h1 makes that check fail, so the title falls back to the file name.

• In millicast/getting-started/index.mdx and theolive_versioned_docs/version-v1/getting-started.mdx, the h1 now comes before the imports and notices. Most other pages with a rebranding notice already use this order (e.g. theoplayer/web/index.mdx). MDX hoists imports, so they can appear after the h1.
• In docusaurus.config.ts, the parseFrontMatter hook now fails the build when a doc page (not a _partial) has no front matter title and no detected contentTitle:

if (!frontMatter.title && !path.basename(params.filePath).startsWith('_') && !parseMarkdownContentTitle(result.content).contentTitle) {
  throw new Error(`${params.filePath}: Missing page title. Move the h1 heading to the top of the document ...`);
}

These two were the only pages that tripped the check. The built titles are now "Getting started with OptiView Real-time Streaming" and "Backend" (the THEOlive v1 page's h1).

Link to Devin session: https://dolby.devinenterprise.com/sessions/3c8f1fdea34b4fce8ed086d5a11a16c1
Open in Devin Desktop: https://dolby.devinenterprise.com/desktop/session/3c8f1fdea34b4fce8ed086d5a11a16c1?variant=devin
Requested by: @MattiasBuelens

[devin-ai-integration]

I'll fix CI failures and address comments from users with write access. I'll skip comments containing "(aside)".

• Disable automatic comment, CI, and merge conflict monitoring