fix(sdk-coin-tao): fix _outputs accumulation and case-insensitive verify

Two correctness bugs identified by post-commit review:

1. ClaimRootTransaction.loadInputsAndOutputs() used push() without
   resetting _outputs/_ inputs first. The base TransactionBuilder calls
   loadInputsAndOutputs() on every build(), so repeated build() calls
   accumulated duplicate entries in _outputs. Fixed by resetting both
   arrays at the top of the method before delegating to super and
   before any push — consistent with how the base Transaction class
   handles Send/Staking paths via assignment.

2. Tao.verifyTransaction() compared txParams.type with the string
   literal 'StakingClaim' using strict equality. WalletPlatform delivers
   intentType as lowercase ('stakingclaim'), causing the bypass to be
   skipped and execution to fall through to super.verifyTransaction()
   which accesses _to/_amount (absent on ClaimRootBuilder) and throws
   'missing recipients in txParams' for a valid claim transaction.
   Fixed with toLowerCase() comparison.

Also strengthen tests: add case-insensitive lowercase test for
verifyTransaction and assert explanation.fee.fee value (tip=0 fallback).

Ticket: SI-1171
Session-Id: ab70e181-1628-4e73-9662-8ef3fe0426ba
Task-Id: 091af7ce-ed42-4177-9ee0-2231917f41fa

Author: ashutoshkumar-6

modules/sdk-coin-tao/src/lib/claimRootTransaction.ts

@@ -30,6 +30,9 @@ export class ClaimRootTransaction extends SubstrateTransaction {
       return;
     }
 
+    this._outputs = [];
+    this._inputs = [];
+
     super.loadInputsAndOutputs();
 
     const decodedTx = decode(this._substrateTransaction, {

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

@@ -59,7 +59,8 @@ export class Tao extends SubstrateCoin {
   /** @inheritDoc */
   async verifyTransaction(params: VerifyTransactionOptions): Promise<boolean> {
     // claimRootWithHotkey carries no transfer recipient — skip recipient validation.
-    if (params.txParams?.type === 'StakingClaim') {
+    // Compare case-insensitively: WalletPlatform may deliver intentType as lowercase.
+    if (params.txParams?.type?.toLowerCase() === 'stakingclaim') {
       return true;
     }
     return super.verifyTransaction(params);

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

@@ -573,6 +573,14 @@ describe('Tao:', function () {
         result.should.be.true();
       });
 
+      it('should return true for lowercase stakingclaim type (WalletPlatform intentType)', async function () {
+        const result = await baseCoin.verifyTransaction({
+          txPrebuild: { txHex: claimSignedHex },
+          txParams: { type: 'stakingclaim' },
+        });
+        result.should.be.true();
+      });
+
       it('should return true for transfer tx with no recipients provided', async function () {
         const result = await baseCoin.verifyTransaction({
           txPrebuild: { txHex: rawTx.transfer.signed },

modules/sdk-coin-tao/test/unit/transactionBuilder/claimRootBuilder.ts

@@ -151,6 +151,8 @@ describe('Tao ClaimRoot Builder', function () {
       explanation.outputAmount.should.equal('0');
       explanation.changeAmount.should.equal('0');
       explanation.fee.type.should.equal('tip');
+      // tip=0 is falsy → || '0' fallback fires; assert the fee value is correct
+      explanation.fee.fee.should.equal('0');
       explanation.outputs.length.should.equal(1);
       explanation.outputs[0].address.should.equal(hotkey);
       explanation.outputs[0].amount.should.equal('0');