fix(sdk-coin-polyx): fix address creation flow for Polyx

Before this change, `TransactionBuilderFactory.getWalletInitializationBuilder()`
threw `NotImplementedError` and `Polyx.requiresWalletInitializationTransaction()`
inherited the base class default of `false`. Together these caused the
wallet initialization transaction to never be built or enqueued, so
the CDD DID-registration step was skipped and address creation
subsequently failed because the chain initialization was never
triggered.

Fix: route `getWalletInitializationBuilder()` to the existing
`getRegisterDidWithCDDBuilder()` implementation, and override
`requiresWalletInitializationTransaction()` to return `true` on the
`Polyx` coin class (inherited by `Tpolyx`). This matches the pattern
used by other coins that require on-chain initialization (Canton,
Starknet) and correctly signals to the SDK wallet layer that a
CDD registration transaction must be submitted before an address
can receive funds.

Add unit tests verifying both behaviors for polyx and tpolyx.

Ticket: CECHO-58
Session-Id: 0594e2d8-7ed3-4626-ad92-ec5f2f0d5f8c
Task-Id: 3a7836f7-b547-445f-9860-54583a5ab35f

Author: nvrakesh06

modules/sdk-coin-polyx/src/lib/transactionBuilderFactory.ts

@@ -1,4 +1,4 @@
-import { BaseTransactionBuilderFactory, NotImplementedError } from '@bitgo/sdk-core';
+import { BaseTransactionBuilderFactory } from '@bitgo/sdk-core';
 import { BaseCoin as CoinConfig } from '@bitgo/statics';
 import { decode } from '@substrate/txwrapper-polkadot';
 import { TransferBuilder } from './transferBuilder';
@@ -153,8 +153,8 @@ export class TransactionBuilderFactory extends BaseTransactionBuilderFactory {
     return new V8NominateBuilder(this._coinConfig);
   }
 
-  getWalletInitializationBuilder(): void {
-    throw new NotImplementedError(`walletInitialization for ${this._coinConfig.name} not implemented`);
+  getWalletInitializationBuilder(): RegisterDidWithCDDBuilder {
+    return this.getRegisterDidWithCDDBuilder();
   }
 
   from(rawTxn: string): TransactionBuilder<TxMethod, SupportedTransaction> {

modules/sdk-coin-polyx/src/polyx.ts

@@ -367,4 +367,9 @@ export class Polyx extends SubstrateCoin {
       },
     };
   }
+
+  /** @inheritDoc */
+  requiresWalletInitializationTransaction(): boolean {
+    return true;
+  }
 }

modules/sdk-coin-polyx/test/unit/polyx.ts

@@ -360,4 +360,15 @@ describe('Polyx:', function () {
       });
     });
   });
+
+  describe('requiresWalletInitializationTransaction', function () {
+    it('returns true for polyx', function () {
+      const polyxCoin = bitgo.coin('polyx') as Polyx;
+      polyxCoin.requiresWalletInitializationTransaction().should.be.true();
+    });
+
+    it('returns true for tpolyx', function () {
+      baseCoin.requiresWalletInitializationTransaction().should.be.true();
+    });
+  });
 });

modules/sdk-coin-polyx/test/unit/transactionBuilder/transactionBuilderFactory.ts

@@ -3,6 +3,7 @@ import should from 'should';
 import {
   TransactionBuilderFactory,
   TransferBuilder,
+  RegisterDidWithCDDBuilder,
   V8TransferBuilder,
   V8HexTransferBuilder,
   V8TokenTransferBuilder,
@@ -247,4 +248,24 @@ describe('Tao Transaction Builder Factory', function () {
       );
     });
   });
+
+  describe('getWalletInitializationBuilder', function () {
+    it('returns a RegisterDidWithCDDBuilder instance for tpolyx', function () {
+      const factory = new TransactionBuilderFactory(coins.get('tpolyx'));
+      const builder = factory.getWalletInitializationBuilder();
+      should.ok(
+        builder instanceof RegisterDidWithCDDBuilder,
+        'expected RegisterDidWithCDDBuilder from getWalletInitializationBuilder'
+      );
+    });
+
+    it('returns a RegisterDidWithCDDBuilder instance for polyx', function () {
+      const factory = new TransactionBuilderFactory(coins.get('polyx'));
+      const builder = factory.getWalletInitializationBuilder();
+      should.ok(
+        builder instanceof RegisterDidWithCDDBuilder,
+        'expected RegisterDidWithCDDBuilder from getWalletInitializationBuilder'
+      );
+    });
+  });
 });