feat: add validatorSignatures to InterchainTransaction type

Ordered verifier signatures used to compute validatorBlockhash
(SHA-256 of concatenated UTF-8 bytes of each base64 sig, saved_at ASC).
Enables independent recomputation of the on-chain committed value.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/types.ts

@@ -180,6 +180,8 @@ export interface InterchainTransaction {
   status: string;
   validatorBlocks: string[];
   validatorBlockhash: string;
+  /** Ordered verifier signatures used to compute validatorBlockhash. In saved_at ASC order. */
+  validatorSignatures: string[];
   signature: string;
   coveredPrimeChainIds: string[];
 }