feat: complete wgcloak v1 transports

fuzz/fuzz_targets/fuzz_http3_parser.rs

@@ -0,0 +1,26 @@
+#![no_main]
+
+use std::collections::HashMap;
+
+use libfuzzer_sys::fuzz_target;
+use wgcloak::transport::http3::{
+    decode_auth_challenge, decode_capsule, decode_http_datagram, is_auth_accept,
+    verify_auth_response, AuthChallenge,
+};
+
+const MAX_INPUT: usize = 64 * 1024;
+const MAX_DATAGRAM: usize = 16 * 1024;
+
+fuzz_target!(|input: &[u8]| {
+    let input = &input[..input.len().min(MAX_INPUT)];
+    // All of these are in-memory parsers. decode_http_datagram bounds the
+    // copied payload, while the capsule/auth parsers only copy this bounded
+    // input or fixed-size fields.
+    let _ = decode_http_datagram(input, 0, MAX_DATAGRAM);
+    let _ = decode_capsule(input);
+    let _ = decode_auth_challenge(input);
+    let _ = is_auth_accept(input);
+    let challenge = AuthChallenge { bytes: [0; 32] };
+    let clients = HashMap::new();
+    let _ = verify_auth_response(&challenge, input, &clients);
+});