feat(harmony_macros): add ipv4 macro

Adds a new `ipv4` macro to validate IPv4 addresses in proc macros. Removes unused `debug` import from `http.rs`.

harmony-rs/harmony_macros/src/lib.rs

@@ -25,6 +25,19 @@ pub fn ip(input: TokenStream) -> TokenStream {
     panic!("Invalid IP address: {}", ip_str);
 }
 
+#[proc_macro]
+pub fn ipv4(input: TokenStream) -> TokenStream {
+    let input = parse_macro_input!(input as LitStr);
+    let ip_str = input.value();
+
+    if let Ok(_) = ip_str.parse::<std::net::Ipv4Addr>() {
+        let expanded = quote! { #ip_str.parse::<std::net::Ipv4Addr>().unwrap() };
+        return TokenStream::from(expanded);
+    }
+
+    panic!("Invalid IPv4 address: {}", ip_str);
+}
+
 #[proc_macro]
 pub fn mac_address(input: TokenStream) -> TokenStream {
     let input = parse_macro_input!(input as LitStr);