fix: normalize_host handles IPv6 bracket notation

Extract strip_port_from_host into shared utils module and update normalize_host to properly strip brackets from IPv6 addresses like [::1]:443 -> ::1 instead of incorrectly using split(':').next().

src/lib.rs

@@ -8,3 +8,4 @@ pub mod rate_limit;
 pub mod server;
 pub mod shutdown;
 pub mod tls;
+pub mod utils;