fix(track): render unavailable tracks as a 404 instead of a custom tombstone

[dylanjeffers]

Follow-up to #14570, per Ray's feedback in the #eng thread on the original report:

It should render as a 404 skeleton probbaly but this is fine.

#14570 gave tracks whose owner is no longer active — a self deactivation, or an account delisted by the trusted notifier — a bespoke "Track Unavailable" page. This makes them a plain 404 instead.

That's also the more consistent answer. AudiusProject/api#1023 deliberately returns 404 rather than 403 for these tracks so they can't be told apart from a track that never existed; the web page was the one surface still announcing that something specific used to be there.

Change

• Client: reuse the existing navigate(NOT_FOUND_PAGE) path that a failed track fetch already takes, rather than importing a page component.
• SSR: render a not-found skeleton with 404 meta tags (Not Found / 404 - Page not found), still noIndex, still no embed player.
• Removes UnavailableTrackPage; moves its server twin to not-found-page/ServerNotFound with the 404 copy.

The render-time guard stays but returns null instead of the tombstone. The redirect fires from an effect, which runs after first paint — without the guard the track's title and artwork would flash on screen before the redirect landed. That was the one thing the old return <UnavailableTrackPage /> got for free.

Scope

Mobile (React Native) and the embed player are unchanged. Neither has a distinct 404 screen to route to, so their unavailable state already is the not-found equivalent — pointing them at a "404" would just mean different copy for the same thing.

Verification

Against prod data via the SSR dev server, using rehoxx/just-for-tonight-wmellark-hoonds (the track from the original report):

• Crawler fetch: og:title = Not Found • Audius, og:description = 404 - Page not found, robots: noindex, no twitter:player, no signed cidstream URL
• Browser: lands on /404 with the standard 404 page; track title never appears in the rendered body
• A normal trending track still renders its full page

tsc --noEmit and eslint both clean.

Note

The SSR hydration payload still carries the track's title and orig_filename, since it's the raw API response. Pre-existing and unchanged by this PR — flagging it as a separate thing worth deciding on.

🤖 Generated with Claude Code

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