feat: complete wgcloak v1 transports

fuzz/fuzz_targets/fuzz_direct_packet.rs

@@ -0,0 +1,15 @@
+#![no_main]
+
+use libfuzzer_sys::fuzz_target;
+use wgcloak::protocol::direct::parse_packet_bounded;
+
+const MAX_INPUT: usize = 64 * 1024;
+const MAX_DATA_PAYLOAD: usize = 16 * 1024;
+
+fuzz_target!(|input: &[u8]| {
+    // Keep the harness itself bounded even if the engine is configured with a
+    // larger input size. The parser performs structural checks before copying
+    // DATA payloads.
+    let input = &input[..input.len().min(MAX_INPUT)];
+    let _ = parse_packet_bounded(input, MAX_DATA_PAYLOAD);
+});