feat: Tycho encoder validation

Validates:
- Proper sequence of input, output, and first/last swap tokens for wrap/unwrap cases
- All solutions contain at least one swap
- Only exact in solutions are inputted (since we don't yet support exact out)

src/encoding/evm/constants.rs

@@ -0,0 +1,10 @@
+use alloy_primitives::hex;
+use lazy_static::lazy_static;
+use tycho_core::Bytes;
+
+lazy_static! {
+    pub static ref NATIVE_ADDRESS: Bytes =
+        Bytes::from(hex!("0000000000000000000000000000000000000000").to_vec());
+    pub static ref WETH_ADDRESS: Bytes =
+        Bytes::from(hex!("c02aaa39b223fe8d0a0e5c4f27ead9083c756cc2").to_vec());
+}