File servers stream to EOF for open-ended media ranges; more than ~6 <video> on one file starves the browser's connections (check hangs) #6029

What happens

Every HyperFrames file server answers an open-ended range request (Range: bytes=N-) with the rest of the file. Browsers send that form for <video>/<audio>, read until their media buffer is full, then stop reading but keep the response open. Each media element therefore holds one HTTP/1.1 connection for as long as the page is open.

Chrome allows 6 connections per host. When a composition has more than about six <video> elements on the server's host, the rest of the page's requests wait for a free connection that never comes.

The pattern is common: one long recording split into trimmed segments, one <video> per kept range on the same source file.

Seen with

• hyperframes check hangs. It stalls at 0% CPU with the default 9 samples on a composition with 58 <video> segments of one 858 MB recording; --samples 5 gets through. Confirmed on 0.8.148 by capping open-ended answers at 4 MB in the bundled serveFileWithRange: the default check then passed. The code is unchanged on main as of v0.8.183.
• Unbounded memory in a long-open preview tab. A separate local server with the same behaviour grew Safari's WebKit Networking process to about 21 GB over a day. The page reloaded often, and every reload re-requested each segment's whole tail. A 4 MB cap fixed it.

Where

All three handlers resolve bytes=N- to end = size - 1:

• packages/cli/src/utils/staticProjectServer.ts: serveFileWithRange
• packages/cli/src/utils/compositionServer.ts: buildRangeResponse
• packages/studio-server/src/routes/preview.ts: the inline Range branch in the static route

Suggested fix

For audio/video, cap an open-ended range at a fixed piece (4 MB worked here): end = min(size - 1, start + PIECE - 1), returned as a normal 206 with Content-Range: bytes start-end/size. Media elements already request the next range as they play and seek, so playback is unchanged. Bounded start-end and suffix -N requests stay as they are. Each response then finishes and frees its connection.

Repro shape

1. Make a long video (a few hundred MB is enough).
2. In a composition, add 8 or more <video> clips with the same src, each with its own data-start, data-duration and data-media-start.
3. Run npx hyperframes check . with the default sample count.

I'm happy to send a PR covering the three handlers if this is the direction you want.