CW-1069-implement-deuro-dapp-support (#2304)

* feat: started dEuro Savings integration

* fix: merge conflict regarding theming

* feat: Add dEuro Savings Screen

* feat: Change DEuro Savings UI

* feat: Complete DEuro Savings integration with UI enhancements and transaction support

* style: remove forgotten print statements

* feat: localize dEuro subtitle

* feat: add approval flow and priority handling to DEuro Savings integration

- Introduced approval flow for DEuro Savings to enable token approvals.
- Added priority handling for deposit and withdrawal operations.
- Updated UI to support approval state and interactions.
- Localized new strings for multiple languages.
- Enhanced transaction handling with separate approval and commit actions.

* feat: add support for ERC20 token approval transactions

- Introduced `signApprovalTransaction` and `createApprovalTransaction` methods.
- Added handling for infinite approvals.
- Implemented encoding for approval transaction data.
- Enhanced transaction creation flow with approval-specific functionality.

* Update UI

* feat: enhance DEuro Savings logic and UI with computed property and fix gradient background

* feat: localize transaction confirmation content for DEuro Savings

* feat: enable interest collection for DEuro Savings with localized support

* fix reformatting [skip ci]

---------

Co-authored-by: tuxsudo <tuxsudo@tux.pizza>
Co-authored-by: OmarHatem <omarh.ismail1@gmail.com>

cw_evm/lib/evm_chain_wallet.dart

@@ -2,6 +2,7 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 import 'dart:math';
+import 'dart:typed_data';
 
 import 'package:bip32/bip32.dart' as bip32;
 import 'package:bip39/bip39.dart' as bip39;
@@ -255,6 +256,7 @@ abstract class EVMChainWalletBase
     required String? contractAddress,
     required String receivingAddressHex,
     required TransactionPriority priority,
+    Uint8List? data,
   }) async {
     try {
       if (priority is EVMChainTransactionPriority) {
@@ -276,6 +278,7 @@ abstract class EVMChainWalletBase
           gasPrice: EtherAmount.fromInt(EtherUnit.wei, gasPrice),
           toAddress: EthereumAddress.fromHex(receivingAddressHex),
           maxFeePerGas: EtherAmount.fromInt(EtherUnit.wei, maxFeePerGas),
+          data: data,
         );
 
         final totalGasFee = estimatedGas * maxFeePerGas;
@@ -478,6 +481,43 @@ abstract class EVMChainWalletBase
     return pendingEVMChainTransaction;
   }
 
+  Future<PendingTransaction> createApprovalTransaction(
+      BigInt amount,
+      String spender,
+      CryptoCurrency token,
+      EVMChainTransactionPriority priority) async {
+    final CryptoCurrency transactionCurrency =
+        balance.keys.firstWhere((element) => element.title == token.title);
+    assert(transactionCurrency is Erc20Token);
+
+    final data = _client.getEncodedDataForApprovalTransaction(
+      contractAddress: EthereumAddress.fromHex(
+          (transactionCurrency as Erc20Token).contractAddress),
+      value: EtherAmount.fromBigInt(EtherUnit.wei, amount),
+      toAddress: EthereumAddress.fromHex(spender),
+    );
+
+    final gasFeesModel = await calculateActualEstimatedFeeForCreateTransaction(
+      amount: amount,
+      receivingAddressHex: spender,
+      priority: priority,
+      contractAddress: transactionCurrency.contractAddress,
+      data: data,
+    );
+
+    return _client.signApprovalTransaction(
+      privateKey: _evmChainPrivateKey,
+      spender: spender,
+      amount: amount,
+      priority: priority,
+      gasFee: BigInt.from(gasFeesModel.estimatedGasFee),
+      maxFeePerGas: gasFeesModel.maxFeePerGas,
+      estimatedGasUnits: gasFeesModel.estimatedGasUnits,
+      exponent: transactionCurrency.decimal,
+      contractAddress: transactionCurrency.contractAddress,
+    );
+  }
+
   Future<void> _updateTransactions() async {
     try {
       if (_isTransactionUpdating) {