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/mod.rs

@@ -1,4 +1,5 @@
 pub mod approvals;
+mod constants;
 mod models;
 mod strategy_encoder;
 mod swap_encoder;