feat(wasm-solana): add Transaction.toBroadcastFormat()

Add toBroadcastFormat() method to Transaction and VersionedTransaction.
Returns base64 encoded transaction for Solana network broadcast.

Ticket: BTC-3002

Author: lcovar

packages/wasm-solana/js/transaction.ts

@@ -131,6 +131,14 @@ export class Transaction {
     return this._wasm.to_bytes();
   }
 
+  /**
+   * Serialize to network broadcast format.
+   * @returns The transaction as bytes ready for broadcast
+   */
+  toBroadcastFormat(): Uint8Array {
+    return this.toBytes();
+  }
+
   /**
    * Get all account keys as Pubkey instances
    * @returns Array of account public keys

packages/wasm-solana/js/versioned.ts

@@ -209,6 +209,14 @@ export class VersionedTransaction {
     return Buffer.from(this.toBytes()).toString("base64");
   }
 
+  /**
+   * Serialize to network broadcast format.
+   * @returns The transaction as bytes ready for broadcast
+   */
+  toBroadcastFormat(): Uint8Array {
+    return this.toBytes();
+  }
+
   /**
    * Get static account keys (accounts stored directly in the message).
    * For versioned transactions, additional accounts may be referenced via ALTs.

packages/wasm-solana/test/versioned.ts

@@ -95,13 +95,15 @@ describe("VersionedTransaction", () => {
 
   describe("id getter", () => {
     it("should return UNSIGNED for unsigned transaction", () => {
-      const tx = VersionedTransaction.fromBase64(LEGACY_TX_BASE64);
+      const bytes = Buffer.from(LEGACY_TX_BASE64, "base64");
+      const tx = VersionedTransaction.fromBytes(bytes);
       // The test transaction has an all-zeros signature (unsigned)
       assert.strictEqual(tx.id, "UNSIGNED");
     });
 
     it("should return base58 signature after signing", () => {
-      const tx = VersionedTransaction.fromBase64(LEGACY_TX_BASE64);
+      const bytes = Buffer.from(LEGACY_TX_BASE64, "base64");
+      const tx = VersionedTransaction.fromBytes(bytes);
       const feePayer = tx.feePayer;
 
       // Add a non-zero signature