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/utils.rs

@@ -0,0 +1,48 @@
+pub fn strip_port_from_host(host: &str) -> &str {
+    if host.starts_with('[') {
+        if let Some(bracket_end) = host.find(']') {
+            &host[..bracket_end + 1]
+        } else {
+            host
+        }
+    } else if let Some(colon_pos) = host.rfind(':') {
+        &host[..colon_pos]
+    } else {
+        host
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn strip_port_plain() {
+        assert_eq!(strip_port_from_host("example.com"), "example.com");
+    }
+
+    #[test]
+    fn strip_port_with_port() {
+        assert_eq!(strip_port_from_host("example.com:8080"), "example.com");
+    }
+
+    #[test]
+    fn strip_port_ipv6_bare() {
+        assert_eq!(strip_port_from_host("[::1]"), "[::1]");
+    }
+
+    #[test]
+    fn strip_port_ipv6_with_port() {
+        assert_eq!(strip_port_from_host("[::1]:8080"), "[::1]");
+    }
+
+    #[test]
+    fn strip_port_ipv6_with_long_address() {
+        assert_eq!(strip_port_from_host("[2001:db8::1]:8080"), "[2001:db8::1]");
+    }
+
+    #[test]
+    fn strip_port_ipv4_with_port() {
+        assert_eq!(strip_port_from_host("192.168.1.1:8080"), "192.168.1.1");
+    }
+}