GHSA-9998-894r-fwvr: Http4s Ember Transfer-Encoding value parsing (TE.CL / TE.0 request smuggling)

## Summary Ember's HTTP/1.1 header parser matches the `Transfer-Encoding` header value with a case-sensitive substring test (`hValue.contains("chunked")`). RFC 9112 §7 requires transfer-coding names to be compared case-insensitively. A request carrying `Transfer-Encoding: Chunked` (capital C) is therefore not recognised as chunked, and Ember falls back to framing by `Content-Length` (or zero if absent) while a compliant intermediary frames the same bytes by chunked encoding. The two parsers then disagree on where the request body ends, enabling HTTP request smuggling (TE.CL / TE.0). …