Fix dx serve proxying of websocket connections established from the browser (#3895)

* better ws request detection

* proxy ws connections

* improve naming

* perform case-insensitive header comparison

* preserve request headers when proxying websocket connection

* avoid side effects in conversion function

* fix websocket proxying for axum 0.8

* remove redundant conversions

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Co-authored-by: Evan Almloff <evanalmloff@gmail.com>

packages/cli/src/serve/mod.rs

@@ -3,6 +3,7 @@ use crate::{AppBuilder, BuildId, BuildMode, BuilderUpdate, Result, ServeArgs, Tr
 mod ansi_buffer;
 mod output;
 mod proxy;
+mod proxy_ws;
 mod runner;
 mod server;
 mod update;